The Mayan number system was the most advanced number system of it's time. Instead of being on based on 10 like our number system is their number system was based on 20.
 They have 19 different digits. When they use numbers larger than 19 they use the the 19 digits to represent a certain amount of 20s, 400s, 8,000s, etc.
 To figure out a number larger than 19 first figure out how many 8,000s you can fit in it. After that figure out how many 400s can go in it and write that number with one of the 19 digits below that. Then do the same thing with 20s and ones.Then write those numbers from top to bottom with the 19 digits.