Population. Hope this helps :D
The Mayan and other Mesoamerican cultures used a vigesimal number system based on base 20 (and, to some extent, base 5), probably originally developed from counting on fingers and toes. The numerals consisted of only three symbols: zero, represented as a shell shape; one, a dot; and five, a bar.
The summer monsoon generally begins in April and lasts through late September, while the winter monsoon arrives
in October and ends in March.
