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 date ...

Here’s a fun clip from BBC Two’s collegiate quiz show University Challenge. Host Jeremy Paxman asks the contestants what day of the week it will be 100 days after Monday. A player named Binnie ...

You may never have heard of modular arithmetic, but you use it every day without the slightest difficulty. In this system, numbers wrap around when they reach a certain size called the modulus; it is ...