When we divide, we're rarely interested in what's left over. In these problems and games, we invite you to take a closer look at remainders and learn about Modular Arithmetic, an important area of Number Theory.

Frances and Rishi were given a bag of lollies. They shared them out evenly and had one left over. But when they shared them with more friends, there were two left over...

In the video, Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can you figure out a way they could stop him?