They say that according to the Mayan calendar the world is going to end this Friday. I don’t think that’s true, but the Mayan calendar is pretty interesting. In fact most of the details of how the Mayans worked with numbers and dates are pretty interesting. They used a base-20 number system which included a written zero.
One of my favorite ways to learn different number systems is to use them to create a clock. Here’s one I wrote which shows the current time in Mayan numerals.
The left column is the current hour, the middle column is the current minute, and the last column is the current second. You can see that it starts with 0 (that bean symbol), then starts adding dots for ones. But when it would reach five dots, it uses a bar to represent five. But since it’s base 20, this only gets to 19 (4 bars and 4 dots). At that point they used a second digit. But unlike our numbers, they typically placed the more significant digit above instead of to the left.
For more information about the Mayan number system, check out this Wikipedia article.