Have you ever wondered what shape a football is? No, it is not a sphere - it is far closer to something called a truncated icosahedron, also known as a "buckyball". It consists of 12 black pentagons and 20 white hexagons and is about the most effective way of creating something nearly spherical out of flat panels. Curious sporting-related mathematical facts like this can be found throughout Eastaway and Haigh's book "How to take a penalty, the hidden mathematics of sport".
Most people think that mathematics consists of either just arithmetic, or a collection of very abstract and technical topics which the layperson has no chance of grasping. But this really is not true: of course many areas are too technical for the non-mathematician, but there are also many beautiful and non-trivial facts which can be expressed in ordinary language for everyone to appreciate.
Early in our mathematical careers, we are introduced to prime numbers. These special integers, which possess no divisors other than themselves and 1, are the building blocks for all the integers. Thus an understanding of the properties of primes, including where to find them, is an essential part of number theory, and any serious discussion of prime numbers will inevitably lead to what is arguably mathematics' greatest unsolved problem: The Riemann Hypothesis.