alt Hacker NewsI use emu48 on my phone emulating the HP-50g, which was almost exactly the same size as the phone so my muscle memory somewhat carries over (minus the tactile feedback of a real keyboard). I still have the physical calculator on my desk at home, with no batteries in it so it's only usable within reach of its USB cable.
Anything that goes beyond what that calculator's UI can reasonably handle is going to end up in a Jupyter notebook or something like that.
Similarly, I still have my HP-42s but I usually use Free42[0] on my phone and tablet. They also have it for desktops. It's great if you like RPN calculators. Or if anyone wants to learn about them, you can use that program and follow along with the original manual(s)[1]. It's nice to be able to handle the order of operations without parentheses.
[0] https://thomasokken.com/free42/ I should send them a donation.
[1] https://literature.hpcalc.org/community/hp42s-om-en.pdf followed by https://literature.hpcalc.org/community/hp42s-prog-en.pdf