Episode 4

In the final heat, two new families compete for the last remaining spot in the semi-finals. The first contestants are the Mohammed family from Watford, made up of IT manager dad Iqbal, keen debater mum Bushra and their sons Zain, 15, an engineering-enthusiast, and Haris, 12, who beat his whole year group in a school maths challenge.

Standing in their way is the orienteering-loving Smith family from Cumbria - keen knitter mum Andy, retired engineer dad Rob, aspiring novelist Ailith, 13, and Ivan, 12, who is passionate about maths.

Leading his team, Iqbal hopes that his logical approach to challenges will take his family to the semi-final, while maths teacher Andy should be in her element with a mental maths test on the horizon.