After beating a plagiarism claim in court, musician Ed Sheeran said that musical coincidences were inevitable with only 12 notes to choose from… but what do the numbers say? Mathematician and concert pianist Eugenia Cheng takes us through the mathematics of music and explains how the power of exponentials mean that just a handful of notes can open up a seemingly endless world of musical variety.

Presenter: Tim Harford
Producer: Nathan Gower
Programme Coordinator: Janet Staples
Sound Engineer: Neil Churchill