Professor of mathematics Ian Stewart from the University of Warwick sets the Science Weekly pub quiz challenge (answers in a separate podcast).
Prof Stewart also discusses the Fibonacci sequence, the mathematics of plants, and his new book Professor Stewart's Cabinet of Mathematical Curiosities.
We speak to Virgin Galactic's president Will Whitehorn about sending older people into space.
Environment correspondent David Adam looks ahead to the UN's climate change summit in Poznan, Poland.
Plus, we analyse a body swap study and ask whether it could lead to a treatment for phantom limb pain.
Nell Boase and James Randerson are also in the pod.
WARNING: you will need a pen and paper for this podcast. Calculators are not permitted!
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