A friend complained about making mistakes on their mobile calculator nowadays because it has significant input lag since an update. Needs a third party calculator app now... I was happy that I could recommend Simple Mobile Tools' calculator, open source donationware and does only what it should. I only know of it because my phone didn't come with a calculator at all, which I found weird too. I use a bunch of their apps actually and they're all great, so this was an easy choice. Not sure what the equivalent for Windows would be, I never saw anyone use an alternative calculator -- unless Google counts but that's not because of problems with calc.exe.
For anyone who hasn't seen these, I recommend them as well. The default calculator works fine for me, but "Simple File Manager" and "Simple Gallery Pro" are fantastic apps that strip out the typical cruft of these tools, and unlike some alternatives (looking at you, Amaze), have no tracking scripts or nag screens.
