The Babylonians counted in base sixty, which is why hours still have sixty minutes and circles have degrees.

The longer version

Sixty is divisible by two, three, four, five, six, ten, twelve, fifteen, twenty, and thirty, which makes splitting quantities into equal parts unusually painless. A system built on it therefore handles thirds and quarters exactly, where a decimal scheme produces awkward repeating tails.

Clay tablets show the scheme in use for astronomy and administration thousands of years ago, and its residue is still everywhere: sixty seconds in a minute, sixty minutes in an hour, three hundred sixty degrees in a full turn. One common explanation is that sixty merges a count of ten fingers with a count of twelve knuckle segments.

Where this entry sits

This section collects odd corners of mathematics, from stubborn prime numbers to counting systems older than modern schools. Expect famous constants, probability puzzles, shapes that break everyday intuition, and numbers far too large to picture. The full list sits on the Numbers and Math page, where every entry is listed in order.