Q: how do i use hexadecimals?
A: instead of 10 digits there are 16. so after 9 it's A, B, C, D, E, F, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E, 1F, 20, etc