Aztec number system

[SAUCEPOT]

How do historians know about the Aztec number system?
Why did the Aztecs need to write down numbers?

[jno]

partly for their calendar, I think; they carved them, and they've since been deciphered
http://en.wikipedia.org/wiki/Aztec_calendar

[dot.hawkes]

As an aside, i have been to Chichan itza and there they have also deciphered the number system, so much so that mel Gibson was able to make a movie paying the exact rate per day to the actors as the mayans paid for their slaves, how cool is that? and i love mel dearly.