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 ...

Rachel first joined Countdown in 2009, taking over from Carol Vorderman RACHEL Riley has been temporarily replaced on Countdown – by a YouTube star. The Channel 4 words and numbers show will undergo ...

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The 33-year-old Countdown favourite, who has been a regular on the post-watershed spin-off series since it first began, said tonight’s instalment was her favourite one she had ever filmed. Taking to ...