If you predate the pocket calculator, you may remember slide rules. But slide rules take a a little skill to use. There was a market for other devices that were simpler or, in some cases, cheaper. One ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This paper sheet gives “simplified ...

This sheet contains information relating to an adder known as the Maric Brain Calculator. Sections discuss how to clear the machine, how to add, how to subtract, how to multiply, and assistance in ...