I’m just young enough that I don’t know how to use a slide rule. We had calculators, the guys the year ahead of me in the pre-calculus math class I took in high school learned to use slide rules. I had a TI SR-51-II.
I made the transition to HP and RPN c. 1979. Late in college I had the original HP-41C with the mag card reader accessory for program and data storage. There are quite a few RPN calculator choices in the Apple App Store. I have one handy on my iPhone and iPad, don’t really use them that much. The spreadsheet pretty well killed calculators.
This thread reminds me I need to get down to see the air museum at Warner Robbins AFB again. It has been 20 years since I’ve been there. It’s a long day trip driving for me.
SR-51-II, with the bright red numbers, was the calculator I had before the HP. Always coveted an HP-41C, but never got one.
Slide rules are pretty easy to use, though I was never a real whiz with one. It’s just adding and subtracting logarithms, plus the trig functions. The really good thing about them is that you learn to be careful about keeping track of orders of magnitude (also, your batteries never give out in the middle of an exam).
Just FYI, this company makes HP clones:
Review of the DM42:
https://www.youtube.com/watch?v=Ong91Ji3iDk
(if you can stand the grating voice...)
So, you live in Rome?