I'm trying to find a calculator as good as my old Texas Instrument TI-89. I liked it so much that I continued to use it for many years on my smartphone with an emulator from F-Droid, also by laziness to find something better and more modern.
But I recently switched from Android to iOS and you can't find a TI-89 emulator on iOS. You have a few web based online but they are not very nice to use.
I got the WolframAlpha app as it is often recommended, but it is super slow and cloud based. And you need to reformulate some queries a lot before it does what you want. However, the Apple app store is full of calculators that all look relatively nice. I havn't found yet one as powerful as the old TI 89 or the Voyage 200, but I guess it does exist.
The closest modern match I found so far is the Numworks emulator app, but it's not as nice.
So what's your favourite calculator ? You may prefer GNU bc in a shell, or a mechanical calculator.
https://cloudflare.f-droid.org/en/packages/com.Bisha.TI89EmuDonation/ https://www.wolframalpha.com https://www.numworks.com
The HP-48G was my favorite, lost with a lot of things due to water damage thanks to a random roof leak leading to a closet. The HP 32S II has been my go-to scientific calculator since college (one random class wouldn't let you use graphing calculators), it's still going strong now 20 years or so later.
Other than those, on a computer, I use the emacs calculator.Reply
Mine would be my DM42, which is a SwissMicros remake of the HP42. I do have a few others within reach, but I do like my RPN, so that's what I go for first.
I'd love a mechanical calculator, though.Reply
HP-11c. Mine is probably new in 1985ish. I think on its 4th set of batteries. I'd love an HP-15c for the additional program memory, but collectors have driven the prices crazy. RPN is super-efficient.Reply
These are pricey but are by far the best calculators I have ever used. I have nostalgia for the 48 series and the quirky Saturn CPU but the ARM based primes are a great follow up.
HP has an official emulator for the prime so you can try before you buy.Reply