Image: "Detail of Codex Dresdensis drawn by Lacambalam" by Lacambalam - Own work. Licensed under CC BY-SA 4.0 via Commons.
We admit—we were pretty excited when we found this awesome Mayan math game, courtesy of the Smithsonian National Museum of the American Indian!
The Mayans were an ancient civilization that lived in Central America from about 2000 BC til as recently as the 1600s! They developed a numerical system that allowed them to express very large numbers and perform complex calculations by utilizing only three symbols to represent numbers. A dot represents 1, a bar represents 5, and a shell represents 0! Below are the numbers 0 to 19:
(Image:"Maya" by Bryan Derksen - Image:Maya.png. Licensed under CC BY-SA 3.0 via Wikimedia Commons.)
The Mayans utilized a vigesimal, or base-20 number system (in contrast, we use adecimal number system, or base-10). Numbers after 19 were written in a vertical place value format using powers of 20 (source). While we think of place value in terms of ones, tens, hundreds, etc., the Mayans' place value system went from the ones to the twenties to the four-hundreds, and so on!
As an example, check out the number 65 in the image below. The three dots on the second tier represent 60 (3 x 20 = 60), and the single bar on the bottom tier represents 5.