The ancient Maya civilization used a vigesimal (base-20) numeral system.

The numerals are made up of three symbols; zero (egg shape), one (a dot) and five (a bar).

For example, 19 is

Digits are stacked with the higher significant digits at the top, so

. =

would be read as 1 11 in base 20 (one "twenties" and eleven "ones") or decimal 31.

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