For something to do with my head, I’m taking the RAC Advanced Ham Radio course. The exam uses a non-programmable scientific calculator. I thought that all my calculators were programmable, but we found this one lurking in the basement and it’s just perfect:
This is one of the few calculators I’ve seen that both displays and takes inputs in SI units. How to put it into SI engineering display mode is explained in this delightful (archived) site Casio fx-115MS.
Entering numbers with SI prefixes is simple: type the number, then Shift and hit the prefix. So to enter 300000, you’d type 300 Shift 4 to get 300 k.
You do have to be a little careful reading the display in this mode, though. The display above reads 221 Ã— 10-3 (from the m at right), or 0.221.
I don’t see any calculator in Casio’s current range that offers this handy feature. Guess I’m lucky I found it before the exam!