Before there were apps for tablets and smartphones, before mathematics education software was easily installed on personal computers, before electronic calculators entered professional practice and ...

Primarily for multiplication and division, the slide rule has two stationary sets and one sliding set of numbers in the center. To multiply, numbers are added; to divide, numbers are subtracted.

Around here we mostly enjoy slide rules. We even have our own collections including some cylindrical and circular ones. But [Mathologer] discusses a recent Reddit post that explains a circular ...

Using the ring itself as a former, he made a wooden base for the router to allow it to slide across the surface without wobbling. The inside wall was cut into sections and glued into a recess in ...