Rachel Riley replaced by 'brilliant mathematician' on Countdown

Mathematician Dr Tom Crawford will stand in for Rachel Riley while she takes a short break to work on another project. Dr Crawford is well-known for his Tom Rocks Maths YouTube account, where he has more than 200,000 subscribers and gained millions of views. He is a mathematician at Cambridge and Oxford Universities, having completed his PhD in applied maths at Cambridge in 2016.Countdown airs on Channel 4 every weekday afternoon from 2.10pm.