A few more early devices. Calculators I inherited from my Dad.



An HP LED display classic, the model 45, a non-programmable scientific calculator. It had multiple memory locations and a rechargeable battery. All the usual scientific functions. Came with a huge blow-molded plastic case worthy of a staple gun and a pleather holster with belt loop, just like the slide rules it replaced.

TI "Business Card", a 1980s mini model. Amortization calculations and boring stuff like that.

Also an interesting Casio folding fx-411. The Casio could compute in hex (including logic operations), degrees/minutes/seconds and fractions. The solar cell made it a poor choice in dark examination halls -- I had one almost exactly like it and made that mistake once.