In a week that explores man's early experiments with numbers, Neil MacGregor describes the British Museum's most famous mathematical papyrus. This shows how and why the ancient Egyptians were dealing with numbers around 1550 BC. This papyrus 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 describes it as "a crammer for a dazzling career in an ancient civil service".