

The Mayan Numerals
Instead of ten digits like we have today, the Maya used a base number of 20. Base twenty was also used in their calendar, developed by astronomers for keeping track of time. They used a system of bar and dot as "shorthand" for counting. A dot stood for one and a bar stood for five. In the following table, you can see how the system of dots and bars works to create Mayan numerals and the equivalent Roman numerals 019.
Because the base of the number system was 20, larger numbers were written down in powers of 20. We do that in our decimal system too: for example 32 is 3*10+2. In the Maya system, this would be 1*20+12, because they used 20 as base. Numbers were written from bottom to top. Below you can see how the number 32 was written:
It was very easy to add and subtract using this number system, but they did not use fractions. Here's an example of a simple addition:
As you can see, adding is just a matter of adding up dots and bars! Maya merchants often used cocoa beans, which they layed out on the ground, to do these calculations. Send email to color@saxakali.com with questions or comments
about this web site. The data for this page was provided by Michielb, a graduate astronomy student living in The Netherlands. It is based on a written summary of a lecture Dawn Jenkins gave on the topic of Maya Astronomy at the February 13, 1995, at the regular meeting of the Cuyahoga Astronomical Association. The HTML version was made by Michiel Berger, who added some information and graphics here and there by Michielb. 