Uploaded March 2025 | Updated September 2026, 2 weeks ago

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Dr Tom Crawford shows off his Pi tattoo to celebrate International Day of Mathematics - or Pi Day - 2025. Footage from Countdown on Channel 4 - watch weekdays at 2:10pm.

Oxford University Mathematician Dr Tom Crawford joins the Countdown team as the numbers expert for 3 weeks to cover for Rachel Riley. Watch at 2:10pm weekdays on Channel 4.

Footage copyright Channel 4.

Watch Tom explain the solutions to the number rounds from his time on the show here: youtu.be/8Ct9fJrU-8U

Tom is Public Engagement Lead at the Oxford University Department of Continuing Education: conted.ox.ac.uk/profiles/tom-crawford

For more maths content check out Tom's website tomrocksmaths.com

You can also follow Tom on Facebook, Twitter and Instagram @tomrocksmaths.
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Support Tom's work via Patreon here: patreon.com/tomrocksmaths