I'm going to have a hard time with this when the school district mandates that my son use a calculator that has an "Equals" key.

We've always been an HP family. RPN all the way. I literally am unable to use a TI calculator (well, they may well have Enter keys now -- I know the newer HP calcs have Equals keys of a sort, which you can ignore). My son will not be using a scientific calculator as broken as the TI ones.

You think I'm joking. I'm not. (I'll probably have to relent and let him use a TI, but I'm going to show him RPN first...)