[HN Gopher] 2-in-1 calculator app adds up to surprise hit for re...
       ___________________________________________________________________
        
       2-in-1 calculator app adds up to surprise hit for retired engineer
        
       Author : CrankyBear
       Score  : 917 points
       Date   : 2022-09-19 19:07 UTC (1 days ago)
        
 (HTM) web link (mainichi.jp)
 (TXT) w3m dump (mainichi.jp)
        
       | PaulHoule wrote:
       | "The number of downloads grew at a sluggish pace at first because
       | the app was designed so that just one calculator is displayed on
       | the smartphone's vertical screen mode, while two are shown only
       | when the screen is rotated on its side. So, many users only
       | thought it was a regular calculator."
        
       | TheSpiceIsLife wrote:
       | Any software calculator that has a tape feature works well for
       | me, I think the built in windows calc app does.
       | 
       | I've been using CalcTape for a few years now, it's a calculator
       | and notepad in one.
       | 
       | https://www.schoettler-software.com/en/calctape/windows
       | 
       | I appreciate the simplicity of the side by side calculator app
       | though.
        
       | xxr wrote:
       | I haven't used this app, but something that makes me smile is
       | that the paid version is only 563KB (the paid version is 4.6MB,
       | and I suppose it's pleasant that the ad SDKs are "only" 4 megs).
       | After seeing every major app take up 100MB+ for years, I had just
       | assumed that there was some kind of static packaging inherent to
       | all iOS apps that jacked the deliverable size up so high. I don't
       | know whether Ueda was deliberately trying to get it as small as
       | possible, or if his design is so elegant that it just naturally
       | led to such a tiny artifact. Either way, as long as the 3.5"
       | floppy is still in its sunset period[0], I suppose it's nice that
       | there's modern software that will still fit on it.
       | 
       | [0]https://www.bbc.com/news/world-asia-62749310
        
         | postalrat wrote:
         | The web app version would probably be 1/10th of that.
        
           | miniBill wrote:
           | I mean... it depends what you want to support. My web
           | calculator [fully client side] is 370kb of JS. It has
           | features that this doesn't have (3d rendering, solving
           | equations), but doesn't have code that this needs (mostly,
           | the keyboard)...
        
           | pwinnski wrote:
           | On the one hand, there's your claim that a web version of
           | TwinCalc should be 56.3K or so. On the other hand, there's a
           | world of existing web apps which are generally very much
           | larger than that.
           | 
           | A smaller footprint than 563K would be a dubious advantage
           | for web apps in either case.
        
           | donkarma wrote:
        
         | auggierose wrote:
         | If it is an app built in Swift, then iOS and macOS ship already
         | with all of its runtime libraries, so the app itself can be
         | very small.
        
         | Someone wrote:
         | > there was some kind of static packaging inherent to all iOS
         | apps
         | 
         | There was for apps using Swift. Before the Swift ABI was
         | frozen, iOS apps using Swift had to statically link the Swift
         | standard library. Nowadays, iOS provides it as a dynamic
         | library.
         | 
         | (and having a stable ABI is quite an accomplishment for a
         | language like Swift. See https://faultlore.com/blah/swift-abi/)
        
           | saagarjha wrote:
           | The Swift libraries are not all that large, perhaps a dozen
           | MB or so.
        
       | Ferret7446 wrote:
       | How odd. I see a lot of discussion about calculators having
       | history and such, but as someone who became acquainted with
       | Emacs's Calc mode at an early age, it seems so strange that
       | calculators with history are a foreign concept to most people.
        
         | MandieD wrote:
         | The vast majority of people outside of Unix-adjacent computing
         | have never heard of, much less used, emacs. More broadly, most
         | people have never used any form of REPL, including the handy
         | PowerShell that has come out of the box with Windows for a good
         | decade now.
         | 
         | This app succeeds because the developer has hit upon an
         | interface that better matches normal users' mental models
         | around calculators.
        
       | DangitBobby wrote:
       | I love this! Also, today I learned that you can scroll through
       | your history in the built-in android calculator by swiping down
       | on the number input field!
        
       | jiveturkey wrote:
       | it's too bad i can only buy one copy of this app. if only apple
       | would allow the purchase of 2 copies. but the universe might
       | collapse then, having reached its poetic end.
        
       | layer8 wrote:
       | This would almost be unnecessary if iOS allowed two instances of
       | the same app to be opened (and displayed in split view). I'm
       | saying "almost" because the integrated app is of course easier
       | for non power users.
        
       | mavhc wrote:
       | Wait until they try a GUI with windows
        
       | imhoguy wrote:
       | Is it only me who sees a humble man enjoying his own ikigai[0] in
       | simple but challenging creation? The photo says it all.
       | 
       | [0]https://en.wikipedia.org/wiki/Ikigai
        
       | frou_dh wrote:
       | Similar to the 80-something Japanese woman who created an iPhone
       | app relating to a doll festival, that was a big news story a
       | couple of years ago.
        
       | dm319 wrote:
       | Some similarities with RPN, except instead of two calculators
       | working on two registers side by side, it's one calculator
       | working on the bottom of several registers.
       | 
       | Both allow you to do complex interim calculations that can be
       | hard to plan out on algebraic alone.
        
       | dpb1 wrote:
       | Some of the strong points of this calculator is the main thing I
       | use in RPN calculators with stacks. It's so helpful for me to
       | duplicate a value and then operate on that, and be able to throw
       | it away if I mess up, sanity check from where I started at
       | intermediate calculations, etc. it's not identical, but many
       | points others are mentioning in this thread are what I value from
       | an RPN stack based calculator.
       | 
       | BTW, for anyone who is comfortable with RPNs, MacOS added the
       | mode to their built-in calculator recently-ish. it's not terrible
       | either. I've switched to it for my default experience. (even
       | though nothing beats the HP 48g, as it's what I'm the most
       | familiar with).
       | 
       | Also, on the article, really cool that someone added this on
       | mobile. I love hearing about devs developing something that fills
       | a niche and does so well. I feel like I'm out of ideas most days.
       | Good for her!
        
         | a_e_k wrote:
         | On that note, I always end up using an HP 48g emulator on my
         | phone as my main calculator app. I've been using Droid48 for
         | many years now [0]. I'd initially looked at most of the native
         | mobile calculator apps before realizing that since I was
         | comparing them all with the HP 48 experience, I might as well
         | just use an emulated HP 48 and be done with it.
         | 
         | On a laptop or desktop, though, I've come to use Emacs Calc [1]
         | pretty heavily. There's a surprising amount of power in it.
         | It's pretty cool to be able to do things like operate on
         | matrices of symbolic expressions via a stack interface.
         | 
         | [0] https://play.google.com/store/apps/details?id=org.ab.x48
         | 
         | [1]
         | https://www.gnu.org/software/emacs/manual/html_mono/calc.htm...
        
           | adhesive_wombat wrote:
           | I find Hiper to be almost perfect for its clearer UI than a
           | rendering of a real device and, especially, for its prominent
           | binary and hex radix modes.
           | 
           | But it lacks the stack undo of the 48 emulators.
        
         | [deleted]
        
         | dusted wrote:
         | I came here to write this.. Yeah, I'd have thought that dual-
         | calculator thing was brilliant if I hadn't turned to RPN.
        
         | deepspace wrote:
         | I was thinking the same thing while reading the article. I have
         | been using RPN calculators for 40 years, and it has become
         | second nature to manipulate the stack to have two calculations
         | going at the same time, and then merging them, if needed.
        
           | bollu wrote:
           | What's the RPN based calculator you use on your terminal? I'd
           | love to learn!
        
             | self wrote:
             | dc, perhaps.
        
             | deepspace wrote:
             | To be honest, I mostly use a physical calculator
             | (Swissmicros DM41L, which is an HP41CX clone). Second
             | choice is the i41CX+ app on my phone. The HP41 keyboard and
             | operational patterns were etched into my brain at
             | university, since my first engineering calculator was an
             | HP41C.
             | 
             | I have used rpncalc and T_REX
             | (https://isene.org/2021/02/T-REX.html) in the terminal, dc
             | or gforth in a pinch.
        
             | dr-neptune wrote:
             | Not sure what the parent uses, but emacs has calc, which is
             | a RPN calculator with lots of features (including history
             | and intermediate results) and can be used in the terminal
        
       | yieldcrv wrote:
       | Wow, I need to look for more contrived but accepted user
       | experiences to fix!
        
       | wishfish wrote:
       | That's a brilliant & simple idea. I love it. Makes me wonder if
       | anyone's made a small screen spreadsheet? Seems like that would
       | be the obvious next step.
       | 
       | Something like a default of 3x4 or 4x4 cells. Would have most of
       | the basic spreadsheet functionality, and maybe simple graphs to
       | show comparisons. Interface designed for touch on a six inch
       | screen.
        
         | fomine3 wrote:
         | I'd like to use this for daily driver.
        
         | maguay wrote:
         | Numbers runs on iOS--not terribly easy to use, per se, but
         | absolutely gets the job done. There was a light version of
         | Excel even on the BlackBerry-styled Windows Mobile phones that
         | similarly was great for, oh, comparison pricing or converting
         | multiple values other tiny math jobs.
         | 
         | One specifically designed for phones with a very limited
         | feature set, though? That could be very handy.
        
         | giarc wrote:
         | I've always wanted a browser extension (or similar) that opens
         | a small 10x10 spreadsheet so I can quickly do some
         | calculations. For example, if you are shopping online and have
         | various options that all have different shipping costs etc. It
         | would be nice to do a quick breakdown of costs without having
         | to open Excel.
        
           | wishfish wrote:
           | It's a little surprising Google hasn't done this already. A
           | small (maybe inline, maybe floating) popup that gives you a
           | little grid. Would autosave to Sheets. That would be perfect.
           | 
           | Anyways, that's a great idea you have. I never knew I wanted
           | this, but now I want it very badly.
        
             | themarkn wrote:
             | It's pretty fast to pop open a new tab and visit
             | sheets.new, I do this a lot but not everybody knows about
             | it (and the rest of the .new TLD) The in-line floating
             | thing is not too attractive to me. But yeah, new window,
             | sheets.new, split screen, you're spreadsheeting before you
             | know it.
        
               | pjot wrote:
               | Same goes for
               | 
               | - docs.new
               | 
               | - slides.new
               | 
               | Super cool!
        
             | giarc wrote:
             | I think floating would be best. I just had a use case for
             | this today. Was shopping for furnace filters online. They
             | come in a variety of packs (some single, some 4, 12x). They
             | don't always list the per unit cost, so it would be nice to
             | quickly open a floating 10x10 table, list out a few options
             | and get a per unit breakdown to find the best deal.
        
             | aj7 wrote:
             | If you paste an expression into the search box... Try it
             | with (66/6)^2/2
        
           | wolpoli wrote:
           | That would be a great idea! That's the perfect use for the
           | "spreadsheet implemented in Browser" submissions we have seen
           | over the years!
        
         | rayrag wrote:
         | https://tinysheet.com/
        
           | DangitBobby wrote:
           | Unfortunately limited to 2x10 only
        
             | wolpoli wrote:
             | I found a few other options:
             | 
             | http://xem.github.io/sheet/
             | 
             | https://chrome.google.com/webstore/detail/quick-
             | spreadsheet/...
        
       | shabbatt wrote:
        
       | ChicagoBoy11 wrote:
       | What a fantastic example of "make something people want." Kudos
       | to him... and so inspiring!
        
       | cobaltoxide wrote:
       | Personally I find it embarrassing that we use a device with
       | gigabytes of RAM and millions of pixels to emulate a 19-button
       | device from half a century ago.
        
         | fomine3 wrote:
         | Yeah buttons should be rendered with ray tracing and deep
         | learning
        
         | pvillano wrote:
         | It's probably hard to come up with a better interface. A pocket
         | calculator can be operated with very little cognitive load.
         | It's easy to memorize because things don't move and it's easy
         | to discover because ~every action is always visible.
         | 
         | It's also good enough. Most people don't need more than a
         | pocket calculator. Sometimes I use WolframAlpha, very modern,
         | but I type my query on a keyboard whose design predates the
         | calculator (QUERTY in <1873 vs "10-key" calculator in 1902)
        
       | noobermin wrote:
       | I think this is why I prefer using the python idle as a
       | calculator. You can assign an expression to a variable, but you
       | can always scan up (assuming your terminal window is tall enough)
       | to see what expression you used to calculate it. People are
       | saying how this is the point of memory on calculators but once
       | you save to M you basically need to remember what's in there.
       | Seeing what you did to calculate whatever is better.
       | 
       | In a way then, the python idle is like this but with many
       | calculators side by side.
        
         | Georgelemental wrote:
         | I like qalc (https://github.com/Qalculate/libqalculate) as a
         | command-line calculator. It has all the basic repl features,
         | but also excellent units support and other useful math-oriented
         | things.
        
         | bee_rider wrote:
         | Python is fine, although I find that Octave gets me to "doing a
         | calculation" in a couple fewer keypresses.
        
       | hnjst wrote:
       | I'm still completely baffled that we nowadays almost all have in
       | our pocket a device able to run something like
       | https://f-droid.org/en/packages/jp.yhonda/.
        
       | ycombinete wrote:
       | Just bought this for my iPad, which apple inexplicably doesn't
       | bundle with their calculator app.
        
       | icedistilled wrote:
       | Why don't calculator apps at the very least display the current
       | calculation like the casio FX-95? The current options of basic or
       | scientific for mac/ios would be 100x better. The ticker tape only
       | partially solves it.
       | 
       | FX 95: https://www.casio.com/intl/scientific-
       | calculators/product.FX...
        
       | asimpletune wrote:
       | Improving upon the design of a calculator app is incredibly
       | difficult. And before people complain that it's not improved, yes
       | it is. For most people, this is way better. Congrats to him, he's
       | living the dream. Building software that does a job, and then
       | getting paid for that software. I just hope he doesn't suffer too
       | many copycat apps.
        
         | FrasiertheLion wrote:
         | This article made me realise why I use a python shell over a
         | calculator app. It's nice to refer back to my previous
         | computations and results. Several people here mention RPN; I
         | work in tech, definitely understand stacks and get that I would
         | be able to view my previous computations. Yet it's not
         | something I took the time to discover, there were always other
         | ways.
         | 
         | I've always believed that there is still a lot of low-hanging
         | fruit left in crafting user friendly experiences for consumer
         | facing applications. Who would have guessed this would be the
         | case even in the design space of something as fundamental as
         | calculators! ~20k paid users seems surprisingly large. But I'm
         | not plugged into the app dev scene, so perhaps this isn't
         | unusual.
        
         | gustavorg wrote:
         | > I just hope he doesn't suffer too many copycat apps.
         | 
         | There were 2k clones of flappy bird within a month of its
         | release. By now there must be at least a dozen programmers
         | copying this idea (Twin-Calc) for other platforms, myself
         | included.
        
       | qwezxcrty wrote:
       | I don't see how this works better than any scientific calculator
       | that shows history. Also don't understand why he put two sets of
       | keyboards, to me it just doesn't make sense.
       | 
       | Marginally related: if you are looking for a non-sucking
       | calculator app on desktop or mobile, try an emulator of a (modern
       | or retro, at your choice) HP or TI graphical calculator. My
       | personal favorite is the emulator of HP Prime.
        
         | NavinF wrote:
         | Umm of course history is superior. So are named variables. You
         | and me are not the target audience.
         | 
         | Ever noticed how normal people hit both C and CE several times
         | on physical calculators because it's not obvious what those
         | buttons do? That's the target audience.
        
         | codeulike wrote:
         | Its immediately intuitive without having to think about it. Its
         | two calculators. Its magnificent.
        
       | effnorwood wrote:
        
       | savrajsingh wrote:
       | This is the perfect example of how we, as devs, way overthink
       | what people actually want / are comfortable with.
        
       | easygenes wrote:
       | For me the killer convenience calculator on mobile has been
       | Soulver. The UI is just perfect for making it easy to string
       | together calculations without taking up too much screen real
       | estate. Irritatingly, the Mac app is available still, but it has
       | been pulled from the iOS App Store for a long time, and it's not
       | on any other platforms. If something like Soulver existed cross
       | platform I would have it installed on everything.
        
       | 1970-01-01 wrote:
       | So he took a niche device and made it an App. Smart!
       | 
       | https://www.casio.com/us/basic-calculators/product.DV-220/
        
         | jiveturkey wrote:
         | yo dawg, i heard you like calculators ...
        
         | pvillano wrote:
         | That's a fun idea: remaking good products that no longer meet
         | the volumes for mass production, but still have enthusiasts who
         | could finance a limited run. Like the new Commodore 64
        
       | paxys wrote:
       | What's interesting is that saving the results of a previous
       | operation to memory and recalling/clearing them (M/MR/MC buttons)
       | has been standard in calculators since the very beginning. It
       | just has the most non-obvious user experience in the world so
       | most people don't even know about the feature.
        
         | cyanydeez wrote:
         | Eh, that's not the problem being solved.
         | 
         | I have the same issue programming when I get popups for various
         | autocomplete or method description or whatever.
         | 
         | Typically, I'm actually focused on the previous line like a
         | hook into my thought process and almost need that hook to get
         | into the next section.
         | 
         | This app is just a simple example of how people visualize the
         | steps into complicated stepping alongside logic.
        
         | RedShift1 wrote:
         | I press both C and CE multiple times on my calculator to reset
         | it so juggling those 3 M buttons is probably a bridge too far
         | for my brain.
        
           | Semaphor wrote:
           | It's been a while since I used a calculator, but yeah. I know
           | that the M-buttons do some storage from when I learned about
           | it in high school, but that was a long time ago.
        
           | closewith wrote:
           | Despite an applied maths degree and a career in informatics,
           | TIL that C is Clear Everything and CE is Clear Entry.
           | Naively, I always assumed the opposite.
        
             | fnordpiglet wrote:
             | Chording them together means "fuck it"
        
               | _jal wrote:
               | An early form of control-alt-delete.
        
               | bee_rider wrote:
               | Alt+hold F4
        
               | v-yadli wrote:
               | which will bring you a loop of a "save before quit?"
               | dialog and then killing it :D
        
             | bitwize wrote:
             | Some scientific calculators have a button marked AC for
             | "all clear", also sometimes in a distinctive color so you
             | know it's important. Features like that appear aimed at
             | people like you and me, who aren't specially trained in
             | calculator use and have to reacquire familiarity with what
             | the buttons do when we use the machine upon occasion.
        
               | julian_sark wrote:
               | To be fair: if it was aimed at people who don't use desk
               | calculators all day, maybe it should say "clear all". You
               | know, in actual words. Or have a picture of a trash can
               | on it. To me, desk calculators with CA/M/MR/MC... are a
               | design fail.
        
         | kube-system wrote:
         | Being able to visually see the number would be helpful. I
         | haven't seen any that visually show what is stored in memory
         | until you recall it. It would be pretty neat if pocket
         | calculators had a second line for that feature.
        
           | tyingq wrote:
           | Yeah, the current Windows calculator has a tab that shows the
           | memory, and I do use it. It would be nice on a physical
           | calculator.
        
         | pleb_nz wrote:
         | It can also be confusing and hard to use for a lot of people
         | and once it's failed for a user once or twice, they'll likely
         | give up with it. I have even succumbed to copy n paste as the
         | cognitive load is less and safer.
         | 
         | This however is very obvious and I think it's a great idea. If
         | I had iOS I think I would install it.
        
         | bee_rider wrote:
         | We could also think of it as a spreadsheet with 2 cells.
        
         | xani_ wrote:
         | I just learned RPM instead of figuring that out. RPN calc with
         | 3-4 lines of stack display is just more convenient
        
         | ketozhang wrote:
         | The design is horrible and a relic of skewmorphism.
         | 
         | Single tally memory is useful on small screens. I just wish
         | they'd display the stored value somewhere.
        
           | jonahx wrote:
           | The design is:
           | 
           | 1. Not skeuomorphic.
           | 
           | 2. Indeed, flat.
           | 
           | 3. Almost identical to the iPhone native calculator, except
           | it uses round-edge rectangles instead of circles.
        
             | stevage wrote:
             | It's skeuomorphic in the sense that the layout is very
             | similar to a physical calculator.
        
               | DrewADesign wrote:
               | Nope. Skeumorphic design uses ornamentation, like
               | textures and interaction animations, to mimic the
               | aesthetic of a physical object. You don't even need to
               | adopt an existing standard interface layout to be
               | skeumorphic. Make those keys look rubber or give it a
               | mock LCD display and you'd be skeumorphic even if the
               | buttons were in a circle around the display.
        
               | bee_rider wrote:
               | It simulates the experience of having two iPhones with
               | the calculator app open next to each-other. iPhones are
               | physical objects.
        
               | joemi wrote:
               | By that logic, _any_ app is skeuomorphic by default just
               | by existing. IMO that's being too liberal with the
               | definition.
        
               | whywhywhywhy wrote:
               | No they're not. Look into the history of the term it's
               | from the era where your music playing app would function
               | exactly like a CD player.
               | 
               | For example
               | 
               | iPhone calculator is a skeuo calculator because it has
               | the same layout and limitations of a physical calculator.
               | 
               | Soulver is a non-skeuo calculator because it is built
               | around the benefits of a computer and ignores the history
               | of a calculator.
        
               | thrwaway23236 wrote:
               | > iPhone calculator is a skeuo calculator because it has
               | the same layout and limitations of a physical calculator.
               | 
               | In that case you can also consider the iPhone "dialer" to
               | be skeuomorphic, as it has the same layout as the old
               | physical buttons. The digital keyboard is also using the
               | same layout as a physical keyboard.
               | 
               | One could argue that on a touch screen, the buttons are
               | there because it is the most efficient layout and not
               | because it looks like a physical calculator. In that
               | case, it is not skeuomorphic.
        
               | whywhywhywhy wrote:
               | The iPhone dialer definitely is. I'm not saying that's
               | bad or anything, some things are better being
               | skeuomorphic if it helps users understand the interface.
               | It's just the actual user interface design discussion
               | gets drowned out by how honestly for lack of a better
               | word embarrassing most digital design discourse is in
               | general it's been changed into more of an art direction
               | debate than a UI design one.
               | 
               | >One could argue that on a touch screen, the buttons are
               | there because it is the most efficient layout and not
               | because it looks like a physical calculator. In that
               | case, it is not skeuomorphic.
               | 
               | It definitely is designed to be a physical calculator
               | though to the extent it is an actual copy of a famous one
               | [1], and has all the limitations of a physical calculator
               | even mincing the memory limitations of a physical
               | calculator.
               | 
               | [1] : https://www.wired.com/images_blogs/gadgetlab/iphone
               | _braun.jp...
        
             | schadara wrote:
             | From the second image, it appears he set the cornerRadius
             | too high and the buttons became almonds. If that's what he
             | was going for, then perhaps it IS skeuomorphic? /s
        
         | samstave wrote:
         | When I was a little kid in the 80s, there was a SQRT function
         | on my calculator and I would typ in numbers then hit that
         | button and log the results in a scratch pad...
         | 
         | and the thing is that even using the M/MR/MC feature was
         | foreign to me...
        
         | hn_throwaway_99 wrote:
         | It's not just that people don't know about the feature. I'd
         | argue having the side-by-side calculator views is fundamentally
         | different (and much better) than just having a memory-
         | store/memory-recall button. E.g. in this app, you get to see
         | the full equations that went into a particular set of
         | calculations as you go back and forth.
        
           | romwell wrote:
           | It's the Norton Commander of calculators
        
           | jonny_eh wrote:
           | Exactly, the problem with memory buttons is it's easy to
           | forgot (ha!) what's in the memory. With the sibling
           | calculator, you can see everything.
        
             | [deleted]
        
             | layer8 wrote:
             | You also can't perform another calculation with the stored
             | value (other than M+/M-) while also keeping the current
             | accumulator.
        
             | psychphysic wrote:
             | I constantly want this feature.
             | 
             | Everywhere.
             | 
             | Making meetings on the outlook app on my phone for work is
             | a complete and utter chore. I can't look at emails at the
             | same time. While I end up popping everything out on my PC
             | on my phone that's not possible.
             | 
             | This is basically the same thing and on a desktop I'd
             | pushed I end up dumping all the info in the scratch pad of
             | an Emacs session phones just don't let you do that.
        
               | mrb wrote:
               | On standard Android phones you can do it. I just tried
               | split screen (GMail on top, Google Calendar at the
               | bottom) and you can create or edit a calendar event while
               | having an open email on top. Looks like this on my phone
               | (Android 13): https://ibb.co/51skSCw
        
               | ClassyJacket wrote:
               | Yes but they mean having an Outlook email open while
               | making a calendar event in Outlook. It's the same app.
               | Since they mentioned Outlook at all it's almost certainly
               | a work email.
        
               | chaostheory wrote:
               | Just use the web version of Outlook and it's possible.
        
               | psKama wrote:
               | That's still possible to do on Android as long as the app
               | allows for that. For example when you compose e new email
               | in Gmail Android app, it starts as a new instance/app and
               | you can split screen, so that you can go through other
               | emails on top half while writing a new email at the
               | bottom half, which is pretty handy when you try to refer
               | to some other email or to fetch some info from another
               | email.
        
               | jorvi wrote:
               | I believe Samsungs have this feature.
               | 
               | I wish iPhones either supported it in landscape, or got a
               | feature called 'slide-over' from iPadOS, where you can
               | float another app on top of your current app, off-screen
               | to the right. There's a little edge you can then grab and
               | pull over your current app to quickly peek or copy info
               | back-and-forth. When you're done you just slide back the
               | 'slide-over' app.
               | 
               | It's a really clever feature. And I know swiping on the
               | gesture bar exist, but it doesn't have nearly the same
               | rapid fluidity of slide-over.
        
               | baq wrote:
               | modal windows should be banned by the geneva
               | convention...
        
         | quickthrower2 wrote:
         | I use M, MR, MC buttons but having 2 calculators is kind of
         | cool too, it is a fun idea.
        
         | cjohnson318 wrote:
         | I was reading about doing log-log calculations on slide rules
         | the other night, and I can tell you that M/MR/MC is even worse
         | than that.
        
         | michaelgrafl wrote:
         | I know this feature, but I'd much more prefer the workflow of
         | having two calculators side by side.
        
         | dr_dshiv wrote:
         | A light dawns, thank you.
        
         | irrational wrote:
         | I know about the feature, I just have no clue how to use it and
         | don't use a calculator enough to bother looking up how to use
         | it.
        
       | anotheryou wrote:
       | I can highly recommend https://bbodi.github.io/notecalc3/notecalc
       | 
       | Web based Soulver-like calculator that is a bit more like
       | scripting.
       | 
       | totally different, but wonderful.
        
         | insane_dreamer wrote:
         | Nice. Gonna bookmark this one.
        
         | haint_ wrote:
         | This is great, but I can't seem to copy the result. Is it just
         | me?
        
           | anotheryou wrote:
           | oh weird, not just you. In the export preview you can, hope
           | there is a better way though.
        
           | anotheryou wrote:
           | found it out:
           | 
           |  _hit ctrl+c in any line_ (without any character selection)
           | to copy the result.
        
             | haint_ wrote:
             | Thank you, but I wish we could manually select it and copy
             | the desired part (for example when converting days to
             | seconds I'm only concern about the actual seconds, not the
             | "seconds" suffix)
        
       | jqpabc123 wrote:
       | So is this significantly better than just using store and recall?
        
         | flowerbreeze wrote:
         | In my opinion it is, because I don't need to recall what I
         | recall.
        
           | jqpabc123 wrote:
           | When I need to recall what I recall, I just hit [MR].
        
             | hn_throwaway_99 wrote:
             | Which causes you to then lose what you have typed in the
             | screen already.
             | 
             | TBH, these semi-snarky "How is this any different from
             | MS/MR?" responses are like "Why should a CPU ever need more
             | than 2 registers?" to me.
        
               | jqpabc123 wrote:
               | _Which causes you to then lose what you have typed in the
               | screen already._
               | 
               | Then hit [MX] instead. Problem solved with 1 button
               | instead of a whole extra calculator.
               | 
               |  _" Why should a CPU ever need more than 2 registers?"_
               | 
               | The question in this case is "Why should a calculator
               | only have 2 registers". This approach doesn't scale
               | beyond 2 numbers?
               | 
               | Personally, I prefer RPN where I have a whole stack to
               | work with.
        
               | hn_throwaway_99 wrote:
               | What is the [MX] button? I don't think I've ever seen
               | that on a calculator.
               | 
               | TBH, though, this is still kind of like arguing that
               | people should never need GUIs because you can do
               | everything on the command line. There is a pretty
               | obvious, fundamental difference being able to see
               | everything on the screen at the same time, vs having to
               | remember what you stored in memory (and what calculations
               | went into it).
               | 
               | As for RPN, while I agree most people are never taught
               | RPN.
        
               | jqpabc123 wrote:
               | [MX] = Memory Exchange --- Swap display and memory
               | 
               | A better, more intuitive solution than any of the above
               | with available screen real estate is a history tape of
               | prior resultants created automatically.
               | 
               | Multiple prior resultants (not just 2) always available
               | to view --- no action required.
               | 
               | To recall a number from the tape into the active
               | accumulator for further manipulation, simply click the
               | number.
               | 
               | To remove a number from the tape, click and drag right or
               | left. To reorder, click and drag up or down.
        
               | [deleted]
        
               | tremon wrote:
               | But then, why should my phone screen be limited to only 2
               | calculators?
        
               | jqpabc123 wrote:
               | Instead of more calculators, all you really need is just
               | better design. See above.
        
         | criddell wrote:
         | It's only $3. How much better does it need to be to be worth
         | $3?
        
           | jqpabc123 wrote:
           | What happens if I am working with 3 or 4 different values?
           | 
           | This duplicate calculator method doesn't scale too well. A
           | history tape is a better option --- just as intuitative but
           | more capable/flexible.
        
             | criddell wrote:
             | Are you looking for people to tell you this is what you
             | should be using?
             | 
             | If it doesn't work for you, then use something else.
        
             | outworlder wrote:
             | Then you start approaching spreadsheet territory.
        
               | jqpabc123 wrote:
               | With a history tape calculator, you can easily and
               | intuitively juggle 5 or 6 different numbers --- not just
               | 2.
        
         | naikrovek wrote:
         | in terms of ease of use and visibility yes I would say this is
         | more than significantly better.
        
         | zem wrote:
         | absolutely
        
       | injidup wrote:
       | A spreadsheet with two cells only. Take that bloatware excel!
        
         | jiveturkey wrote:
         | underrated comment
        
       | syntheticnature wrote:
       | "If I had asked people what they wanted, they would have said
       | faster horses." -- attributed, apparently wrongly, to Henry Ford.
       | 
       | Those of us who know RPN and other options are likely to squirm
       | at this app, but in this case the "faster horse" approach seems
       | to be easy for people to pick up and understand.
        
         | klipt wrote:
         | Horses are self driving so if you count the billions invested
         | into self driving cars, I guess we really do want faster horses
         | ;-)
        
           | KaoruAoiShiho wrote:
           | Not aware of any horse from which I can watch a movie on and
           | not have to control at all.
        
             | NoGravitas wrote:
             | Depends if the horse knows where it's going. If it's going
             | home, no problem.
        
             | wikfwikf wrote:
             | There are plenty of accounts of drunk Victorian men letting
             | their horses lead themselves home.
        
       | ctrlc-root wrote:
       | If you're looking for something similar on the desktop I use
       | SpeedCrunch to address the same need. You can chain calculations
       | and refer back to previous entries while seeing your history.
       | 
       | https://heldercorreia.bitbucket.io/speedcrunch/
        
         | mjcohen wrote:
         | Can't open it on MacOS Monterey because owner cannot be
         | verified.
        
       | LordHeini wrote:
       | Not sure if this app can do stuff like cross multiplication or
       | run the same operations on both calculators.
       | 
       | But this app reminded of something similar.
       | 
       | There is an old school double mechanical pinwheel calculator:
       | 
       | https://www.youtube.com/watch?v=qnlzKCFP0sU
       | 
       | It was probably mostly used for coordinate calculations.
       | 
       | I own one of those brunsvigas (the single stage one) and it is
       | fascinating what these things can do.
       | 
       | A mechanical calculator with enough didits can solve cross
       | multiplication rather easily.
        
       | [deleted]
        
       | colinmhayes wrote:
       | The base calculator on iPhone is pretty horrible in my
       | experience, but I guess I'm not the target audience. I've really
       | enjoyed eduCalc Classic. It has graphing functionality plus a
       | "guess the function" game based off graph + table which has
       | become my go to plane activity. The unit converter is super
       | useful too.
        
         | fsckboy wrote:
         | iPhone calculator apps are one of those areas I'm "happy to pay
         | for an app but I don't want to pay for a dozen of them to
         | figure out which are garbage and which I like"
        
         | Gibbon1 wrote:
         | The one on windows is terrible and getting worse with each
         | iteration. It's obvious no one with any authority cares and
         | doesn't understand why they should.
         | 
         | Can you drag and drop a number into the calculator? No. I rest
         | my case.
        
           | mavhc wrote:
           | It's open source, just add the feature yourself
        
         | DevX101 wrote:
         | The default macOS calculator app is also terrible. I can't
         | figure out how to do simple multiplication on it. I'm sure
         | there's an answer but I also don't care to find out. If me
         | typing `5*6` then clicking enter doesn't yield the expected
         | result then the UX is the problem, not me.
        
           | ghewgill wrote:
           | If you have an Enter button on the screen, then you are in
           | RPN mode [1]. See the View menu to turn off RPN mode.
           | 
           | 1: https://en.wikipedia.org/wiki/Reverse_Polish_notation
        
         | mejutoco wrote:
         | What is even worse is the ipad has no default calculator (or
         | weather app).
         | 
         | I was so surprised it did not exist I ported the iphone app as
         | a pwa using Typescript and wrote about it here.
         | 
         | https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-po...
        
           | HellsMaddy wrote:
           | iPad finally [0] has a default weather app in iPadOS 16, but
           | still no calculator.
           | 
           | [0]: https://www.theverge.com/2022/6/6/23156804/apple-
           | weather-app...
        
             | vxNsr wrote:
             | What's even harder to understand is why there isn't a good
             | 3rd party iPad calculator app. This doesn't feel like a
             | difficult problem to solve, and yet here we without an
             | intuitive, good looking calculator for the iPad.
        
               | mejutoco wrote:
               | Last time I link to my project, I promise. I think it
               | really applies in this case. https://getcalculator.app/
               | 
               | It is a pwa, so you can add it to the home screen.
        
               | vxNsr wrote:
               | I saw that but I don't like it because it uses periods
               | instead of commas.
        
               | mejutoco wrote:
               | I see, you mean for the thousands separator. It was not
               | localized, you are right.
        
               | RockRobotRock wrote:
               | just wanted to link Craig's response to why there isnt a
               | calculator for iPad: https://youtu.be/Q2aaCDNjWEg?t=900
        
               | vxNsr wrote:
               | Yea yea yea. That's why I said 3rd party. I know they
               | long ago decided not to make an app and have given up on
               | the idea. But you'd think someone would step up in their
               | place and make something useful.
        
       | tobr wrote:
       | What a wonderful kludge. People can't imagine that they would be
       | able to go back and edit, or even see, the history of their
       | calculations, so putting two calculators side by side seems like
       | a brilliant idea.
       | 
       | It's like if a new word processor consisted of two faithfully
       | recreated typewriters, with a special button to send the most
       | recently typed word back and forth between them.
        
         | kube-system wrote:
         | > It's like if a new word processor consisted of two faithfully
         | recreated typewriters, with a special button to send the most
         | recently typed word back and forth between them.
         | 
         | There's a lot of diff tools that essentially do exactly this.
        
         | jldugger wrote:
         | Indeed, this is, like, a solved problem on every other
         | platform! Apple instead designs their apps after tech from the
         | 80s[1] and is now stuck there for life.
         | 
         | [1]: https://www.creativebloq.com/design/iconic-calculator-
         | inspir...
        
           | pwinnski wrote:
           | Indeed, it's a solved problem on iOS too! This story isn't
           | about someone releasing a new app into a desolate marketplace
           | without any calculator apps (and hey, turn that iOS default
           | calculator sideways for some fun), it's a human interest
           | story about someone releasing a new app into an already-
           | crowded market with a slightly new twist, and finding success
           | there.
        
         | vxNsr wrote:
         | The issue is that the default Calc doesn't let you see history
         | and nearly every single 3rd party calc doesn't follow iOS
         | design principles, just doesn't look very good, and are often
         | inexplicably slow.
        
           | brimstedt wrote:
           | Why does a calculator need to look good?
        
             | vxNsr wrote:
             | Why does anything need to look good?
        
         | asddubs wrote:
         | a calculator with a history being superior was my first thought
         | too. there are advantages to this approach too, however. The
         | history is selective, so if you make a mistake/typo, that isn't
         | now permanently in your history as a footgun to go back to and
         | re-make. here you have two states and you have full control
         | over them.
         | 
         | of course you could also just have a history where you can
         | delete individual items, but this also makes the interface more
         | complicated and might not be as intuitive (and requires more
         | discipline)
        
       | jjnoakes wrote:
       | It'd be cool to take this a step further - allow for a tree-like
       | setup of as many calculators as you want. Each number in one
       | calculator's equation could be expanded out into a separate
       | calculator where the number was computed, etc.
        
         | pyinstallwoes wrote:
         | Memoize and precompute every calculation over a merkle tree
         | distributed on a decentralized network using content
         | addressable memory hashed to every calculation as the hash you
         | say?
         | 
         | Yeah love it.
        
       | fyloraspit wrote:
       | This is basically the same reason I default to speedcrunch for my
       | calculator app. It has a nice visible and interactive history of
       | calculations.
        
         | iisan7 wrote:
         | Currently a big fan of https://clcalc.net/.
         | 
         | I went through calculator withdrawal after I left Windows XP
         | and the great (for its time) Powertoy Calculator at
         | https://www.rarst.net/software/powertoy-calculator/.
         | 
         | I wanted to like speedcrunch but I abandoned it, because I've
         | found that it takes longer to load (4-5 seconds or more) than I
         | need to have it open (1-2 seconds).
        
           | haint_ wrote:
           | Thanks, it works great, but I found it better to have 2
           | sides: expressions on the left and results on the right.
           | Maybe I'm already too familiar with Numi, lol.
        
       | chacha21 wrote:
       | An opportunity to post again my thoughts about software
       | calculators !
       | 
       | https://chachatelier.fr/chalk/article/chalk.html
        
         | Liquid_Fire wrote:
         | Have you ever tried Qalculate? I don't see it mentioned in your
         | article. It feels like it addresses most of your points for
         | creating Chalk, and it's already cross-platform.
        
           | chacha21 wrote:
           | Most people didn't understand that my goal was not to
           | benchmark all existing calculator apps. It is on purpose that
           | I did not mention all "pretty good" softwares, because I
           | cannot know them all.
           | 
           | The article I wrote wants to mention every point that should
           | be adressed (in my opinion) to make a good calculator.
           | Qalculate, like many others, does address some of them.
           | 
           | But as far as I know, only Chalk addresses _all_ of them.
        
       | jhallenworld wrote:
       | My daughter is struggling with this problem: on TI-84s, "(-) 3
       | x^2 Enter" gives -9. Personally, I think that if you have a
       | dedicated negation operator it should have a higher precedence
       | than power, but at the very least the calculator could highlight
       | what it's doing.
       | 
       | "Hypercalc" the Android app does it, but TI-84 is the standard..
        
         | weberer wrote:
         | I'm not sure what the parenthesis around the negative sign is
         | supposed to accomplish. Generally you put it around two or more
         | operators.
        
           | jhallenworld wrote:
           | It's how the key is labeled.
        
         | Georgelemental wrote:
         | > a dedicated negation operator it should have a higher
         | precedence than power
         | 
         | I prefer the traditional precedence; it ensures - 3 ^ 2 = 0 - 3
         | ^ 2
        
           | jhallenworld wrote:
           | I understand the argument, I just wish that the most standard
           | school calculator would highlight somehow what it's doing
           | 
           | Another one is "2 ^ 1 / 2 Enter". Some calculators give 1,
           | newer ones give sqrt(2).
        
         | macintux wrote:
         | Obligatory but futile plug for HP RPN calculators.
        
           | cfraenkel wrote:
           | Seconded. But I'm afraid RPN is an endangered species. Who's
           | learning it anymore?
        
             | kccqzy wrote:
             | Probably every computer science student learns it in order
             | to implement something useful after learning about the
             | stack.
        
       | ilos wrote:
        
       | aj7 wrote:
       | A huge strength of the original HP9100A programmable calculator,
       | http://archive.computerhistory.org/resources/text/HP/HP.9100...,
       | was that ALL 3 rpn stack registers were visible AT ONCE ON THE
       | CRT.
       | 
       | So he has resurrected the original blank slate engineer's intent;
       | Osborne realized that people would be uncomfortable "knowing"
       | stuff was in hidden registers, as apparently a great deal of non-
       | technical people are today, 52 years later.
        
         | Severian wrote:
         | Wow, that's a good looking brochure. I always loved that style
         | of illustration.
        
       | quartz wrote:
       | The best feature on the Mac's built in calculator is the paper
       | tape ([?]+t) which I stumbled on ages ago while accidentally
       | having the calculator open and trying to open a new tab in my
       | browser.
       | 
       | I always leave it open now and it has saved me countless times.
       | Really with the iOS version had this feature built in as well.
        
         | hn_throwaway_99 wrote:
         | Thanks for the tip! Interestingly, I found it weird how the app
         | handles order-of-operations.
         | 
         | That is, if you type 1 + 2 / 2, the answer shows up as 2 and
         | the paper tape shows                 1 + 2 / 2       = 2
         | 
         | However, if you type 1 + 2 = / 2 (that is, you type equals
         | after the 1 + 2, which will show 3 on the screen, before typing
         | the / 2 part), the last line of the paper type shows
         | 1 + 2 / 2       = 1.5
         | 
         | They need to add some parentheses in there.
        
           | contingencies wrote:
           | It's the accepted order of operation in maths that you
           | resolve multiplication and division before addition and
           | subtraction.
           | 
           | While the single-value-view of a calculator removes visual
           | context, if you are banging out multi-step calculations as a
           | power user not having the standard order of operations would
           | be odd.
           | 
           | The workaround, as you say, is to just press enter (equals)
           | after each required subtotal. This is pretty semantically
           | clear, that is - if you consider a traditional keyboard to
           | even be a thing that young people are familiar with - and
           | that is getting arguable!
           | 
           | Key corollary issues to the single-value-view nature of
           | computer calculators are that they pull a lot of (now obtuse)
           | cultural context from physical calculators plus regular
           | mathematical context, none of which is obvious to occasional
           | computer calculator software users.
           | 
           | It's probably high time this stuff was rejigged. Thanks for
           | the paper tape tip!
        
             | 5fOleL5Eo2So8qi wrote:
             | Their stated issue is that pressing enter after the
             | 'subtotal' is _not_ clear because it shows as `1 + 2  / 2`
             | in the history instead of `(1 + 2) / 2`.
        
             | hn_throwaway_99 wrote:
             | To be clear, I'm not arguing that the results from the
             | calculator are wrong, and I totally agree that how it
             | handles order-of-operations is correct.
             | 
             | What I am arguing is that the visual display in the "Paper
             | Tape" view is wrong because it displays different answers
             | for the same values.
        
               | contingencies wrote:
               | Oh sorry totally missed that 5AM here :)
        
           | nonsapreiche wrote:
           | or a /n
        
         | wazoox wrote:
         | Qalculate as such a feature and is my preferred calculator app
         | :)
        
         | faxmeyourcode wrote:
         | Woah, thanks! This is an awesome feature I never would have
         | found on my own
        
         | kaushikc wrote:
         | Thanks! This is handy.
        
         | aasasd wrote:
         | Android's calculator also has the history, invoked by pulling
         | down on the display part. (Perhaps obvious to everybody here,
         | but after the discussion on how the memory function is unclear
         | to people, I'm not so sure.) Also that history is saved between
         | launches, which happens to be extra useful for me.
        
           | paledot wrote:
           | No, I've been using the Android calculator for years and
           | never realized that it could do that. This is the problem
           | with "clever" UX...
        
             | aasasd wrote:
             | Coincidentally, history is also available via the three-
             | dots menu =)
        
             | wolpoli wrote:
             | I never clued in to the fact that the little bar below the
             | calculator screen meant that you could pull it down to show
             | history either.
        
           | crumpled wrote:
           | History is nice. I do wish it had the memory buttons.
        
             | aasasd wrote:
             | You can just select and copy, and then paste. The whole
             | expression is editable as a line of text.
        
           | crumpled wrote:
           | Thanks to this post, I played with the history and discovered
           | that if you tap an expression in your history, it becomes the
           | current expression.
        
           | contravariant wrote:
           | Oh, that is useful.
           | 
           | Now if only I could calculate the log of something by
           | pressing 'log' that would be nice.
        
             | tzot wrote:
             | I think that my Android phone (a Chinese model with Android
             | 11 Go) has _the_ Android calculator, which IIRC was based
             | on the old SGI Irix calculator.
             | 
             | If to the right of the 4 basic operators +, -, x, / you
             | have a vertical strip (greenish in my case), you can slide
             | it to the left and have access to various other
             | operators/functions, including log.
             | 
             | Being based on the old SGI calculator, you can also slide
             | any result to the left to get as many digits after the
             | decimal point as you like.
             | 
             | e.g. slide in the extra ops, press p, then start sliding
             | the 3.1415... result.
        
       | abrax3141 wrote:
       | Seems like if you allowed swapping out a background set of sub
       | calculators, and provide inter-calculator ops on the front two,
       | you've recreated an elegant cross between the RPN and standard
       | calculator models.
        
       | apike wrote:
       | > For example, if a user calculates "89 x 15 = 1335" on one
       | calculator and taps the arrow key, the result "1335" will be
       | displayed on the other calculator, allowing the user to continue
       | a problem while the previous equations are still shown on the
       | screen. This makes it easy to notice errors.
       | 
       | While the UI is very different, the key benefit described here
       | reminds me a lot of Soulver: https://soulver.app/
       | 
       | I love Soulver for how quickly it lets you throw together quick
       | guesstimates and sanity checks. The ability to incorporate
       | previous results by reference and update those on the fly greatly
       | improves the clarity and my confidence in my experience.
        
         | nick0garvey wrote:
         | I make heavy use of Soulver. Really quick way to do some quick
         | calculations with good unit conversion.
         | 
         | e.g. I can write hosts = 100; disk_space_used = 10MiB/s * hosts
         | * 3 days as TiB
         | 
         | And it works as expected. Powerful tool when doing capacity
         | planning or other load calculations.
        
         | l1tany11 wrote:
         | A lot of these apps have really cool features, but what I miss
         | most from my Ti-89 titanium days back in high school was the
         | readability of the input and output formulas. The pretty print
         | feature becomes increasingly useful as computation gets more
         | complex. Adding these natural language features for things like
         | built in dimensional analysis would really take it to the next
         | level (as things like units were a slow pain on the ti).
         | 
         | Drawing an integral with limits, fractions, exponents, etc on
         | the screen in normal notation provides much easier error
         | checking when your inputs get longer and contain more and more
         | syntax like commas, parentheses, etc.
        
           | m12k wrote:
           | Have you tried the Wolfram Alpha iOS app? It's my go-to
           | simply because it lets me enter the whole formula,
           | parentheses and all, instead of having to chop it up. But it
           | also pretty-prints the input after you enter it.
        
           | maleko48 wrote:
           | Wabbitemu has been my go-to backlit Ti-84 emulator for years
           | on Android. I reach for it before stock calculators every
           | time. :)
        
           | benhurmarcel wrote:
           | I really want to code a calculator app one day that would
           | take input as RPN, but produce an editable pretty print
           | formula instead of just the resulting stack.
        
         | culturestate wrote:
         | I _love_ Soulver, and I hope Zac is at least considering a
         | version for iPad OS.
         | 
         | I switched my portable setup from a MacBook to an iPad Pro last
         | year and Soulver is one of a handful of small-but-useful Mac-
         | only apps that I really miss when I'm not at my desk.
        
           | vl wrote:
           | What's strange is that they used to have Soulver for
           | iPhone/iPad/Mac and then discontinued this version.
        
         | wejick wrote:
         | I just found vscode extension with similar functionality, I can
         | imagine using this from time to time. saving time of opening
         | spreadsheet
         | 
         | https://marketplace.visualstudio.com/items?itemName=nortakal...
        
         | spicybright wrote:
         | Plus one for these sorts of apps! I personally use Numi.
        
         | [deleted]
        
         | insane_dreamer wrote:
         | Looks a lot like Numi (https://github.com/nikolaeu/numi), which
         | I've used for years and found to be extremely useful. (In fact,
         | they're so similar, I wonder if one is a riff off the other.)
         | 
         | For non-Mac, there's an open-source web app called that's
         | similar and looks nice too (haven't used it much):
         | https://github.com/sharkdp/insect
        
         | donatj wrote:
         | I'll need to give Soulver a shot. I use Calca almost every day,
         | and it seems very similar.
         | 
         | http://calca.io/
        
           | pony_sheared wrote:
           | I loved Calca, paid and used it for years, but it seems to
           | have stopped development and I switched OS... So I ended up
           | falling back to Excel
        
         | Minor49er wrote:
         | Every screenshot on the homepage shows an empty window
        
           | phito wrote:
           | They're gifs...
        
         | GranPC wrote:
         | A nice alternative for Linux users that I can recommend is
         | NaSC. Unfortunately not very actively maintained, but I'd say
         | it's very much usable: https://github.com/parnold-x/nasc
        
         | gnyman wrote:
         | I do think Soulver would be a better choice for many. But it is
         | much more powerful, allowing you to do conversions and labels.
         | 
         | So the simplicity of just having two calculators side by side
         | and a fast way to transfer the results is probably exactly what
         | some people need and want. Zero learning curve, just two
         | calculators doing exactly what you expect.
         | 
         | I'm always fascinated by apps and programs that does exactly
         | one thing, but does it really well (sometimes referred to as
         | the Unix Philosophy). I feel it's harder to find tools and apps
         | like these nowadays. Not sure if there are less or if they are
         | just harder to find because of the huge number of apps overall.
         | 
         | [Edit] Writing this comment actually reminded me of this blog
         | https://onethingwell.org/ which highlights software like this.
         | Gonna try to contact the author and see if they want to add
         | this one :-)
        
         | etoulas wrote:
         | There's also https://numi.app/
        
         | m_eiman wrote:
         | I like Soulver, and also Tydlig:
         | 
         | http://tydligapp.com/
        
           | Y-bar wrote:
           | I love Tydlig!
           | 
           | But have not seen a single update in many years now, and
           | there are a few rough edges in iOS 15 I wish they had fixed.
           | Is it abandoned?
        
         | nordicio wrote:
         | Shameless plug for my app Kalkyl which I just released 3.0 of
         | that adds functionality like this + collaborative editing and
         | sharing, dimensional analysis, arbitrarily complex unit
         | conversions, and possibility to define your own functions.
         | 
         | https://apps.apple.com/se/app/kalkyl/id519933025?l=en
        
         | shepherdjerred wrote:
         | Oh this looks great! I use Numi but it is a bit too simple.
         | 
         | https://github.com/nikolaeu/Numi
        
       | WiSaGaN wrote:
       | This is the innovation that everybody would see how obvious it is
       | once it's out. And yet no one thought about making it for a very
       | long time.
        
       | Mathmanjetson wrote:
        
       | asimjalis wrote:
       | This can also be used for what if scenarios based on an
       | intermediate result.
        
       | pyinstallwoes wrote:
       | Reminds me of a two stack push down automata. Stack programming
       | languages. Forth lang.
        
       | gkfasdfasdf wrote:
       | Neat feature, IIRC Apple does not have a default calculator app
       | because they can't make one that sets it apart from other apps as
       | is the 'Apple way'. Maybe they should just adopt this one.
        
         | [deleted]
        
         | kevinslashslash wrote:
         | It's just the iPad doesn't have a default calculator app
         | https://www.howtogeek.com/820792/where-is-the-calculator-app...
        
         | sbierwagen wrote:
         | Both iOS and MacOS have default calculator apps. They should
         | look familiar: he copied the interface design exactly for his
         | app.
        
       | ape4 wrote:
       | I first thought it was going to show results in hex and decimal
       | at the same time.
        
         | spc476 wrote:
         | I wrote my own desktop programming calculator that shows signed
         | and unsigned decimal, octal, hexadecimal and binary at the same
         | time. It also allows you to select 8-bit, 16-bit, 32-bit or
         | 64-bit calculations, and do either signed extend (for
         | converting from a lower bit to higher bit legnth) or zero
         | extend. No floating point results though.
         | 
         | It was a fun project to work on.
        
       | 5fOleL5Eo2So8qi wrote:
       | The hard part of writing a calculator app is not parsing `0.1`
       | versus `.1`. That's trivial. The hard part of writing a
       | calculator app is getting precise answers instead of floating-
       | point answers, and given that he thinks the hard part is parsing
       | `.1`, it probably gets it wrong.
        
         | kccqzy wrote:
         | Solved by https://www.hboehm.info/new_crcalc/CRCalc.html
         | 
         | Also, this is in the Android stock calculator so lifting the
         | code over is easy. See also
         | https://dl.acm.org/doi/10.1145/2911981
        
         | outworlder wrote:
         | That's a really large cognitive leap from such a small amount
         | of data.
         | 
         | Have you considered that they may not be using floating point
         | numbers at all? They might be using arbitrary precision
         | arithmetic. That was probably implemented by a library. So not
         | as much effort as you would think.
        
       | chongli wrote:
       | It's interesting but the duplicate sets of buttons are a big
       | waste of space. My favourite free calculator app is Desmos
       | Scientific (by the makers of the graphing calculator) [1]. This
       | app gives you as many entry lines as you like and they all remain
       | live. You can also define variables and functions in one line and
       | use them in another. In effect, it's like a single column from a
       | spreadsheet.
       | 
       | [1] https://apps.apple.com/ca/app/desmos-scientific-
       | calculator/i...
        
       | furyofantares wrote:
       | This seems pretty smart to me.
       | 
       | I think it's being dumped on because it's a "dumb" solution to
       | something that is a non-problem for all of us here, which is
       | probably why I've never seen this solution before. None of us
       | would think of it.
       | 
       | But I think it's true that while most everyone knows how to use
       | the most basic functions of a calculator, most people don't get
       | any further than that, and this allows them to.
        
         | whywhywhywhy wrote:
         | Although Soulver like apps are definitely a better solution. I
         | actually think this 2 calculator app is kinda genius in the
         | sense that people over 60 can instantly understand it and fit
         | it into their workflow.
        
         | codeulike wrote:
         | I have a degree in Mathematics and I can never remember what C
         | and CE buttons on a calculcator are supposed to do. If you only
         | use them occasionally and in a hurry most calculator apps are
         | frustratingly unfriendly.
        
       | WalterBright wrote:
       | I'm actually kind of shocked. The calculator apps emulate a
       | calculator, but they don't take any advantage of having the phone
       | screen. A proper calculator app would allow you to type
       | 1.6*2/3
       | 
       | and display the equation on the screen, not just the 3.
        
         | newtritious wrote:
         | This one does:
         | 
         | https://jacobdoescode.com/technicalc
        
           | WalterBright wrote:
           | That looks pretty sweet!
        
             | WalterBright wrote:
             | dang, IOS 13 or later.
        
       | FilterSweep wrote:
       | > It is also possible to perform different computations on each
       | calculator. This function comes in handy when the user wants to
       | compare prices to determine which store product is cheaper by the
       | gram, for example.
       | 
       | This adds another use-case outside of the M functions on a
       | standard calc :)
        
       | zie wrote:
       | Neat, but a log of transactions would do the same thing, easier
       | wouldn't it? RPN calculators tend to do this nicely.
        
         | fortran77 wrote:
         | Yes, but not as fast and intuitive, especially for people of a
         | certain age who are used to working with a desk calculator
         | nearby at all times.
        
         | pshc wrote:
         | This two-calculator setup has the advantage of being intuitive
         | to anyone despite having only two storage slots. Or rather
         | _because_ it has only two storage slots and they're always
         | visible in fixed places.
        
       | mrb wrote:
       | What I want is a phone app calculator that works like the Python
       | REPL/console. Save ALL previous calculations. Display the last
       | dozen or so. Can scroll through them. Tap on one to recall it,
       | edit one number, recompute. Done.
       | 
       | This would beat by far the convenience and usability of this
       | 2-in-1 calculator. I would KILL to have this.
       | 
       | In fact, on my laptop, I use the Python REPL as a calculator. I
       | hit Ctrl-T python ENTER. It opens a terminal and I start typing
       | 48*152 ENTER and I see the result. The history of calculations is
       | saved. I can access previous calculations, edit one number and
       | recompute. I see the last 100 lines or so, on one screen.
       | 
       | The only one somewhat usable Python REPL on Android is "Pyonic
       | Python 3 interpreter" but it's clumsy to use as a calculator
       | because it uses the standard alphabetic keyboard so you have to
       | keep switching to the special characters layout to type math
       | operators (-+/...) If this ONE detail would be fixed, and with
       | some minor UI polish I believe it could become more popular than
       | the 2-in-1 calculator...
        
         | Georgelemental wrote:
         | qalc (https://github.com/Qalculate/libqalculate) is my command-
         | line calculator of choice. Its killer feature IMO is the units
         | support
        
           | mrb wrote:
           | Very cool ! For units conversion I use GNU Units. But qalc
           | seems to combine the benefits of both the Python REPL and GNU
           | Units. I just tried the command-line version and noticed it
           | doesn't support recalling the history (UP arrow) and editing
           | calculations. This is unfortunately a deal-breaker :-( Don't
           | have time to submit a patch.
        
             | patrec wrote:
             | It does! Via readline. There must be a problem with your
             | build.
             | 
             | Also, you can get this functionality for even your broken
             | build (or other interactive commandline apps that have no
             | edit history) by just doing something like:
             | alias qalc='rlrwap qalc'
        
               | mrb wrote:
               | Ah, i must not have compiled it with libreadline-dev...
               | And I didn't know about rlwrap!
        
         | odabaxok wrote:
         | The built in Android calculator worked like this for ages and
         | it keeps history forever.
        
           | mrb wrote:
           | The built-in calc sucks: when the keyboard is displayed to
           | edit the current expression, the app can only display ONE
           | previous expression at a time. Sometimes I calculate things
           | and need to refer to 2 or more previous results. I would have
           | to copy paste them one at a time (cumbersome) or memorize
           | them.
           | 
           | If only it could display about a dozen previous results while
           | the keyboard is active... With a Python REPL I can just
           | assign intermediate results to variables.
        
         | cole-k wrote:
         | If you know an APL-like or are willing to learn enough to use
         | as a calculator (there are unfortunately some uncommon things
         | like % being division), there's J on iOS:
         | https://apps.apple.com/us/app/j901/id1483497239. There ought to
         | be a way to get it on Android.
         | 
         | I have an older version of it and it works fine although the
         | keyboard is a little clunky. However, you need to swipe to get
         | to previous computations. I'm not sure if they changed that in
         | the new version.
        
         | goplayoutside wrote:
         | I've been using an app called Calctape[0] for years that sounds
         | similar to what you're describing.
         | 
         | It's essentially a 4-function calculator that records every
         | step on tape, but you can edit any digit anywhere and all
         | related steps are immediately recalculated, like on a
         | spreadsheet.
         | 
         | [0] https://calctape.app/
        
           | mrb wrote:
           | Interesting. Not exactly what I described though (sorry I did
           | not explain very well.) What I meant, you type 2
           | calculations:                 > 1+1       2       > 10+10
           | 20
           | 
           | Then if you tap the first line ("1+1") my ideal REPL would
           | add it to the bottom:                 > 1+1       2       >
           | 10+10       20       > 1+1_ (with the cursor here ready to
           | edit it)
           | 
           | Then you can for examlpe change a 1 to 2, then type ENTER:
           | > 1+1       2       > 10+10       20       > 1+2       3
           | 
           | That way you can easily compute a few things, then compare
           | both the expressions and results of the last few
           | calculations, and quickly make edits/corrections as needed.
        
         | denizozger wrote:
         | http://tydligapp.com/ sounds like what you might be looking
         | for.
        
       | supernova87a wrote:
       | > ... _Ueda recalled, "I thought it'd be easy, but it was
       | unexpectedly hard." ... For example, while there are users who
       | input 0.5 by tapping "0," the decimal point, and then "5," there
       | are also users who only input the decimal point and "5," while
       | omitting the "0." He said, "There were around 100 types of these
       | sort of conditions, and it was a lot of work to solve them_."
       | 
       | I wonder what other kinds of non-trivial calculator behaviors he
       | had to rediscover from scratch?
        
         | ghoward wrote:
         | I wrote a `bc` implementation.
         | 
         | There are more than you would think, yes, but not _terribly_
         | bad. I think he exaggerated a little, and `bc` has more than
         | just a simple calculator.
        
         | thrdbndndn wrote:
         | About this specific case: I also never knew using ".5" to mean
         | "0.5" is a thing, until I lived in the US.
         | 
         | Not sure if it's a US thing or Western world thing, my country
         | (not Japan, but also in East Asia) just doesn't use it.
        
           | loonster wrote:
           | Tangently related... In drafting, with metric numbers a
           | leading zero is required. With English Numbers, omitting the
           | leading zero is proper.
        
             | retcore wrote:
             | Product of the English system here: what are "English
             | numbers"?
             | 
             | I've never seen 0.5 written ".5" going back to Principia.
        
               | loonster wrote:
               | In the drafting world, inch units are commonly referred
               | to as English. So if things are drafted properly, .500
               | would be 1/2 an inch and 0.5 would be 1/2 a millimeter.
               | 
               | (Things are rarely drafted according to specs.)
        
           | nemacol wrote:
           | I picked this up from Excel as it defaults to adding the 0 in
           | "general" formatting.
           | 
           | Without a decimal it will strip leading zeros by default, a
           | setting that has caused me hours of frustration over the
           | years.
        
           | paledot wrote:
           | It's not particularly common in Canada, although I do see it
           | occasionally. The principal problem is that a dot (especially
           | handwritten) is easy to miss, whereas an unexpected leading
           | zero induces the reader to check for a dot.
           | 
           | I don't press the zero button on my calculator when inputting
           | values, though, since it's an extra keystroke for literally
           | nothing.
        
           | Ferrotin wrote:
           | Probably your calculators all support it.
        
             | thrdbndndn wrote:
             | Yeah they do, just didn't know this notation (convention?).
        
               | Ferrotin wrote:
               | Oddly, I don't think I've ever noticed the zero being
               | omitted except casually or to save space in a table, in
               | English. I would expect ordinary writing to include the
               | zero.
        
           | NavinF wrote:
           | That's surprising. People don't say stuff like "try setting
           | power level to point three"? Do they use a different word for
           | the decimal separator?
        
             | thrdbndndn wrote:
             | Nope, we always say "zero point three" (in our native
             | language, of course).
        
               | brewdad wrote:
               | While I tend to use the verbal shortcut, your way is much
               | less likely to be misinterpreted.
               | 
               | "Set the power to point three" sounds the same orally as
               | "Set the power two point three"
               | 
               | The zero makes it unambiguous.
        
               | thrdbndndn wrote:
               | It also helps that in my language, zero, point, and all
               | the numbers are all one-syllable, hehe
        
               | gugagore wrote:
               | "to" is often reduced to something like "tuh", whereas
               | "two" never is.
               | 
               | Except in deliberate word-by-word pronunciation, "one two
               | three" and "one to three" sound different in native US
               | English.
        
         | [deleted]
        
       | tempodox wrote:
       | This is such a nice example of how relatively simple ideas can
       | still be of huge utility.
        
       | mikewarot wrote:
       | This UI has a better _impedance match_ to the way he, and many
       | people who used desk calculators, think. It 's quite elegant.
        
         | jiveturkey wrote:
         | I find it to be very japanese. elegance expressed in such a
         | simple form. blindingly obvious ... now. so hard to arrive at
         | this design choice. i love this. it's poetic.
        
         | PTOB wrote:
         | That's a great way to use that term. I like it very much.
        
       | indigodaddy wrote:
       | Simple and effective.
        
       | adrianomartins wrote:
       | Wow, this is some inspiration right here. Never too late! Also,
       | do you have a pain, build a solutions! Congrats to that retired
       | engineer!
        
         | pluijzer wrote:
         | > Never too late!
         | 
         | From your comment and some other comments and the way the
         | article is written I gather that the engineers age is seen as
         | something novel.
         | 
         | Do people really see 63 as an newsworthy fact? Not trying to
         | troll, I honestly wonder. It is 4 years from retirement in my
         | country and I see many other achievements come from much older
         | people.
         | 
         | I just don't see 63 as anything special or old.
        
           | Sebb767 wrote:
           | It's unusual for people in that age group to be good with
           | computers, as they grew up without them (or at least without
           | them being as ubiquitous as in the last few decades). It's
           | also pretty rare to hit such a sweet spot with an app, which
           | makes it somewhat unusual that someone from that age group
           | managed to do so.
        
       | vertis wrote:
       | I quite like Numi[0] (Mac), also available as part of SetApp[1]
       | 
       | [0]:https://numi.app/
       | 
       | [1]: https://setapp.com/apps/numi
        
       | mfbx9da4 wrote:
       | This epitomizes my passion for coding -- it's the lowest barrier
       | to entry for being an inventor
        
       | aasasd wrote:
       | Total Commander and Ghost Commander on Android solve the problem
       | of two panels in the portrait orientation by displaying one of
       | them and having a button to switch to the other one. However,
       | seeing as some of the success of this calculator app is probably
       | attributed to the 'memory' function being non-obvious to people,
       | I'd guess that a hidden calculator might also put some off.
        
       | angry_octet wrote:
       | New calculator feature request: export the calculation stream to
       | the clipboard and CSV/excel, same as old paper tape calculators.
        
       | fennecfoxy wrote:
       | Really cool project for a retired engineer to do.
       | 
       | Kind of reminds me of the "Notebooks" concept that Jupyter and
       | others use (I dipped my toes in it, not an expert).
       | 
       | Would be nice if he could abstract the calculators to a
       | list/hierarchy of calculations performed, then be able to "open"
       | limitless additional calculators as desired and swipe between
       | 'em.
       | 
       | Being able to see a hierarchy of calculations and say, go back to
       | a parent one and modify the value or part of the calculation
       | itself and have child ones update would be super cool.
        
       | waynesonfire wrote:
       | it's also less keystrokes relative to M/MR/MC technique when
       | chaining computation, since, you have two calculators enable
       | concurrency.
        
       | gfodor wrote:
       | If you liked this app, stay tuned - I am working on a
       | 3-calculator app that increases the utility of this app by up to
       | 50%.
        
         | insane_dreamer wrote:
         | but does it run on the GPU?
        
           | TheOtherHobbes wrote:
           | The calculations are the output of an ML solver trained on a
           | data set generated by corporate accountants.
        
             | stackbutterflow wrote:
             | It's not the result you want but it's the value we think
             | you want.
        
         | misterprime wrote:
         | LOL, can you make it dynamically have as many calculators as
         | there are cores on the CPU and guarantee that each calculator
         | only uses a single unique core for its own calculations?
        
           | meesles wrote:
           | I don't think you need to limit the number of calculators to
           | the number of cores. You can just store the history/results
           | somewhere on disk or in memory. Which core doing the work
           | when you press '=' doesn't really matter in this case unless
           | you're load-testing this calculator.
        
           | megablast wrote:
           | I mean, why?? Do you think the calculator is a heavy CPU
           | view???
           | 
           | You still only use one at a time anyway.
           | 
           | And yes, you could easily have 10,000 calculators or more.
        
             | misterprime wrote:
             | Thanks, sorry. It was just a silly response to a silly
             | comment.
        
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