http://kevintwomey.com/calculators.html
Pretty interesting photos of mechanical calculators including the keys used on them.
Neat shots of mechanical... calculators? (bonus: cool vintag
- chzel
- Location: Athens, Greece
- Main keyboard: Phantom
- Main mouse: Mionix Avior 7000
- Favorite switch: Beamspring, BS, Vintage Blacks.
- DT Pro Member: 0086
They are probably mechanical ones where you would press the rightmost column for 1's, the second column for 10's etc, and then you'd press the operator (+,-,*,/) and repeat.