Dr Tom Crawford’s videos of teaching equations in his underwear have helped him attract more than 200,000 subscribers ...

Maths expert and TV presenter Rachel Riley is set to take a ‘short break’ from Countdown – with Dr. Tom Crawford stepping in ...

Rachel Riley is temporarily stepping down from Countdown while she focuses on another project, with newcomer Dr Crawford ...

Rachel Riley is set to be temporarily replaced on Countdown by mathematician Dr Tom Crawford, as she takes a brief hiatus ...

Channel 4 confirm Rachel Riley’s Countdown replacement - Riley first joined Countdown in 2009 as a replacement for Carol ...

RACHEL Riley has been temporarily replaced on Countdown – by a YouTube star. The Channel 4 words and numbers show will ...

Mathematician Dr Tom Crawford will stand in for Rachel Riley on Channel 4's Countdown while she takes a short break to work ...

Rachel Riley replaced by 'brilliant mathematician' on Countdown - Riley is taking a short break from the Channel 4 show ...

EXCLUSIVE: Countdown star Rachel Riley shared her thoughts on leaving the Channel 4 show just days before it was announced ...

Countdown 's Rachel Riley will be temporarily replaced by YouTube math star, Dr Tom Crawford. It was announced that Riley, ...

An Oxford and Cambridge university lecturer and YouTuber has made his debut on TV quiz Countdown. Dr Tom Crawford, who has ...

Rachel Riley will be replaced as the show's co-host by a mathematician and YouTuber while filming a new project .