> 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.
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.
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.
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.
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
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.
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.
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 :-)
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
Are you suggesting that they're supposed to animate? Because they don't.
Edit: No, they aren't even GIFs. They're MP4s. I have to right-click them and select Play to get them to work, probably because I have autoplay disabled in my browser. So they would have worked if they actually were GIFs, incidentally
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.