Rachel Riley has been temporarily replaced on Countdown by a tattooed YouTube mathematician who teaches equations in his underwear. Dr Tom Crawford, known for his Tom Rocks Maths channel on the ...

Mathematician Dr Tom Crawford will stand in for Rachel Riley on Channel 4’s Countdown while she takes a short break to work on another project, it has been announced. Dr Crawford is well-known for his ...

Countdown's Rachel Riley will be temporarily replaced by YouTube math star, Dr Tom Crawford. It was announced that Riley, Countdown's very own mathematician, will have to step down from her hosting ...