[msarnoff]

I didn’t actually know about the Casio 14-A until now. I almost thought the picture was AI-generated. Four functions squeezed into that compact desktop unit in 1957? Impossible with the technology of the time…

The Casio 14-A was indeed the world’s first all-electric desk calculator. But by “desk calculator,” they literally mean “a desk that is a calculator.” The display/keyboard pictured was literally attached to a desk filled with hundreds of relays and weighed 140 kg. [0]

The “all-electric” claim is interesting. There had been scores of electric calculators for decades (Friden, Marchant, etc.) but were merely driven by an electric motor. The calculations were still performed by gears and cams and linkages.

https://www.casioeducation.com/primary-calculators/14-a

[SoftTalker]

I always heard those old mechanical calculators called "adding machines" presumably because addition is all they could do?

[pwg]

For the old mechanical machines (whether powered by a crank or powered by an electric motor) yes, the term "adding machine" was because, for most, all they could do is add:

https://en.wikipedia.org/wiki/Adding_machine

"Subtraction was impossible, except by adding the complement of a number (for instance, subtract 2.50 by adding 9,997.50)."

A few fancier ones could multiply, but they would do so by repeating an addition some number of repetitions. Nearly all output their results on a paper tape much like "store receipts" today, only printed in ink instead of via thermal transfer paper.

[msarnoff]

You’re not wrong. They work very similar to binary arithmetic: basically the only operations they can do is increment, decrement, and shift left/right (but by 10)

But multiplication is just repeated addition, and division is just repeated subtraction. Some of the highest-end units could do square roots! Check out CuriousMarc’s videos.