I run a TI 83+ emulator on my Android phone when I don't have my physical calculator at hand. Same concept, just learned a different brand of calculators.

built-in calculator apps are surprisingly underbaked... I'm surprised neither of the big two operating systems have elected to ship something comparable to a real calculator built in. It would be nice if we could preview the whole expression as we type it..

I use the NumWorks emulator app whenever I need something more advanced. It's pretty good https://www.numworks.com/simulator/