One of my fellow contributors here recently wrote a post about leap years and why we have them. This reminded me of modular arithmetic and the formula for calculating the day of the week for any ...

The Modular Method of Mahjong Keeping track of the game is an exercise in the useful arithmetic of remainders. So is reading a clock.

Modular arithmetic, even when disguised as a rounding problem, can be just as simple, if not simpler. The technique discussed here works for any constant N , delivers solutions even when x has 32 or ...

An Arithmetic-Geometric Method in the Study of the Subgroups of the Modular Group American Journal of Mathematics , pp. 1053-1133 (81 pages) Published By: The Johns Hopkins University Press ...