Maya numerals

The Maya numeral system is a vigesimal (base-twenty) positional numeral system used by the Pre-Columbian Maya civilization.

The numerals are made up of three symbols; zero (shell shape, with the plastron uppermost), one (a dot) and five (a bar). For example, thirteen is written as three dots in a horizontal row above two horizontal lines stack above each other.

Numbers above 19

Numbers after 19 were written vertically in powers of twenty. For example, thirty-three would be written as one dot above three dots, which are in turn atop two lines. The first dot represents "one twenty" or "1×20", which is added to three dots and two bars, or thirteen. Therefore, (1×20) + 13 = 33. Upon reaching 20² or 400, another row is started (20³ or 8000, then 20⁴ or 160,000, and so on). The number 429 would be written as one dot above one dot above four dots and a bar, or (1×20²) + (1×20¹) + 9 = 429. The powers of twenty are numerals, just as the Hindu-Arabic numeral system uses powers of tens.