A handheld calculator and a slide rule. If the power goes out for a long time, I'll still be doing math while the rest of you chumps will be using your fingers to count to 10.
Yes, learned how with a program on a VAX computer ('80s) using a VT100 terminal. I managed to get through high school and college by hunt and peck, though. Definitely not recommended.
If you don't cinch it up too tightly, it's no more constricting than buttoning the top button on the shirt. Not that wearing one makes any sense, but it's not trying to kill you, either.
No lie, my calculator is solar.