Babylonian numerals

The Babylonians used a base-60 (or sexagesimal) positional numeral system borrowed from the Sumerians.

Sixty was chosen due to its prime factorization 2*2*3*5 which causes it to be divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30. Integers and fractions were represented identically -- a radix point was not explically written but rather made clear by context.

Sexagesimals still survive to this day, in the form of degrees, minutes and seconds in trigonometry and time.

See also: Numeral system, Arabic numerals, Armenian numerals, Chinese numerals, Greek numerals, Hebrew numerals, Indian numerals, Mayan numerals, Roman numerals.