Calculator Unboxing #3 (Casio Watch)

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...

It's the Casio Data Bank Calculator Watch, unboxed for Numberphile by Matt Parker.

Normal Casio Calculator unboxed: http://youtu.be/6aDBGTWsydY

More unboxings: http://youtu.be/eaJtjJNrWf0

Matt Parker: http://www.standupmaths.com