As a child, Kate Ertmann starred in commercials, in soap operas and on Broadway. But acting wasn’t her first love - mathematics was. She considered it to be “a balm" for her brain. And yet societal and teenage pressures made her turn away from maths.

Growing up in Sweden, Sebastian Nillson Qvist loathed maths and found it a real struggle. But he still challenged himself to study it as part of a Political Science and Economics degree. It did not go well.

But still, maths came back into their lives.

In this episode of Sideways, we find out what led them back to mathematics and the impact it had on them. Something host Matthew Syed experienced first hand when a desire to understand inflation and economics led him back to studying for a maths A-Level in his own time and finding it actually enjoyable, rather than a chore as he had at school.

We hear how determination to dominate in the sport of darts can lead to incredible mastery of mental arithmetic from Professor Marcus du Sautoy, who also suggests a novel approach to maths education which he believes could inspire and motivate children. And Field’s Medal winner Professor Efim Zelmanov introduces us to a brilliant young mathematician who was killed in a duel 150 years ago but left behind a theory which keeps all online banking safe.

With Kate Eartmann of katelovesmath.com, Sebastian Nillson-Qvist, Professor Marcus du Sautoy - Simonyi Professor for the Public Understanding of Science and Professor of Mathematics, and Professor Efim Zelmanov - Field’s Medallist and Director of the Shenzhen International Center for Mathematics.

Presented by Matthew SyedProducer: Marilyn RustSeries Editor: Katherine GodfreySound Design and Mix: Daniel KempsonTheme Tune: Ioana SelaruA Novel production for BBC Radio 4