Maths speech

Hey tomorrow I have an interview about a maths role and was asked to prepare a speech about an area of maths for example algebra. I can pick any topic and I don’t know what to talk about, they said that it just has to interest us and I’m very confused on what other questions could come up. Am I supposed to talk about maths in general or focus on a small part of a topic. What should I include in this quick speech?