Slide Rule

A 1972-model, new in package, Sterling slide rule. It’s no longer “new in package” as I’ve bought it specifically to use it whilst we teach our children some higher-level maths. For example, we’re teaching them complex multiplication using the old carry and add method.

She was absolutely astonished when I showed her how to solve things faster on a slide rule than the time it takes to open the calculator app and type in the numbers.