An ancient Egyptian papyrus from around 1550 BC, used to train scribes. It contains 84 different calculations to help with various aspects of Egyptian life, from pyramid building to working out how much grain it takes to fatten a goose. Neil MacGregor, Director of the British Museum, looks at man's early experiments with numbers and discovers how the Egyptians' understanding of mathematics enabled them to build a state machine, which could manage food supplies and even compute the flood levels of the Nile. (Duration: 14 mins)