19 out of 20

Alex Bellos discusses how the Incans used knots in string (Quipu) to record numbers.Check out Brilliant (get 20% off their premium service): https://brillian...

In French culture, it is traditional for all grades to be out of 20 - and many teachers will NEVER give full marks!

Featuring Dr Paul Smith, from the School of Modern Languages and Cultures at the University of Nottingham.

More on French numbers: http://www.youtube.com/watch?v=WM1FFhaWj9w