The number after F in Hexadecimal is: 10 (Hex)
Why?
F (Hex) = 15 (Dec)
The number after 15 (Dec) is: 16 (Dec)
So 16 (Dec) in Hex is: 10
Why?
10 (Hex) = 1 * 16^1 + 0 * 16^0 = 16 + 0 = 16 (Dec)
16 (Dec) = 10 (Hex)
(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, ... )