The oldest surviving pyramid-volume problem
An Egyptian scribe, writing around 1850 BCE, poses this: a pyramid has been truncated flat on top, leaving a frustum. Its square base measures 4 units on a side, its square top 2 units on a side, and its height is 6 units. Using only the arithmetic methods available at the time, find the volume of the solid.
Reveal the answer
56 cubic units. The scribe's recipe — square the base and the top, add their product, multiply by a third of the height — is exactly the modern formula V = h/3 x (a^2 + ab + b^2). This is Problem 14 of the Moscow Mathematical Papyrus, the oldest known correct computation of a frustum's volume.
— Unknown Egyptian scribe, Moscow Mathematical Papyrus — Problem 14, c. 1850 BCE