MAYA NUMERALS

Mayan numerals.

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

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

For example, nineteen (19) is written as four dots in a horizontal row above three horizontal lines stacked upon each other.

Numbers after 19 were written down 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 "1x20", which is added to three dots and two bars, or thirteen. Therefore, (1x20) + 13 = 33. Upon reaching 400, another row is started. The number 429 would be written as one dot above one dot above four dots and a bar, or (1x400) + (1x20) + 9 = 429. The powers of twenty are digits, just as the Arabic numeral system uses powers of tens.^[1]

Other than the bar and dot notation, Maya numerals can be illustrated by face type glyphs. The face glyph for a number represents the deity associated with the number. These face number glyphs were rarely used, and are mostly seen only on some of the most elaborate monumental carving.

In the calendar

In the "Long Count" portion of the Maya calendar, a variation on the strictly vigesimal numbering is used. The Long Count changes in the second place value; it is not 20×20 = 400, as would otherwise be expected, but 18×20, so that one dot over two zeros signifies 360. This is supposed to be because 360 is roughly the number of days in a year. (Some hypothesize that this was an early approximation to the number of days in the solar year, although the Maya had a quite accurate calculation of 365.2422 days for the solar year at least since the early Classic era). Subsequent place values return to base-twenty.