Both, the Maya numeral system and our decimal numbers are positional or place-value notations, which is to say that the same symbols are used to express different orders of magnitude.
There are two major differences:
1. In the decimal system symbols are positioned from left to right in decreasing orders of magnitude, whereas Maya numbers are positioned top to bottom in decreasing orders of magnitude.
2. In the decimal system orders of magnitude progress in powers of ten (base 10), while Maya numbers progress in powers of 20 (vigesimal or base 20).
This app simultaneously displays user generated Maya numbers and their equivalent decimal values at each order of magnitude, as well as the final decimal equivalencies for Maya numbers 1 to 1,279,999,999.