A slide rule is a hand-held, manually operated calculating tool that allows the user to perform multiplication, division, exponentiation, extraction of roots, and various other algebraic operations. The slide rule makes use of a set of logarithmical scales that slide alongside each other in order to perform its function. The computational accuracy of the slide rule depends on its size and on the precision of the printed scales. For instance, a typical 10-inch slide rule allows accuracies of about 0.1%, which is acceptable for many engineering calculations. The slide rule remained an important instrument in the mathematics of science, engineering, and business until the easier-to-use and more accurate electronic calculator replaced it in the 1980s.

The basic slide rule, as shown in Figure 1, consists of two adjacent logarithmical scales (A and B) mounted to slide along each other, and so arranged that a reading on one scale...