If you are in higher education, you know all about the Research Excellence Framework (REF), and where we grade papers for their star rate. A 4-star paper has a world-leading advancement, and where you will be lots of maths and results. But there was a time when research really did contribute massively to changing things, and one of the great was Pierre de Fermat. So let’s have a bit of fun first.

In cryptography we love prime numbers and the mod operator. So let’s take a bet. I think I can predict your answer. First select a number from the following: