A regular slide rule takes advantage of the fact that you can multiply and divide by adding logarithms. Imagine having two rulers marked in inches or centimeters — it doesn’t matter (see the adjoining ...

You may remember that I collect slide rules. If you don’t, it probably doesn’t surprise you. I have a large number of what I think of as normal slide rules. I also have the less common circular and ...

While some (math-phobics) still may relish the simple beauty and non-threatening functionality of the abacus, there are those who have made the transition to more challenging computing gadgets—many ...