This article explains how credit card numbers are defined and the check digit serves to verify their accuracy.
Scheduling games is a little more challenging than one might desire. Here are some tournament formats that sport schedulers use.
There is a long tradition of creating mazes throughout history and across the world. This article gives details of mazes you can visit and those that you can tackle on paper.
This problem is taken from the UKMT Mathematical Challenges.View the archive of all weekly problems grouped by curriculum topic