CamScanner (intuitive and powerful scanner app that processes images exceptionally well and interfaces cleanly with all sorts of other apps) and Hiper Calc Pro (scientific calculator that shows you your input and looks like a classic calculator interface)
That’s great! It’s not super helpful for me, though, since I teach students that often aren’t good at troubleshooting technology issues on their own so I need an app that’s pretty universal and user-friendly. Plus, the question specifically asked about stuff in the Android play store…