Here is the list for quick reference:
0000 = 0
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = 8
1001 = 9
1010 = A (or decimal 10)
1011 = B (or decimal 11)
1100 = C (or decimal 12)
1101 = D (or decimal 13)
1110 = E (or decimal 14)
1111 = F (or decimal 15)
The hex number must be single digit, therefore 10-15 are replaced with A-F.