What numbers is not divisible by 9 81 162 199 1125?
81: 8 + 1 = 9 which is divisible by 9, so 81 is divisible by
9
162: 1 + 6 + 2 = 9 which is divisible by 9, so 162 is divisible
by 9
199: 1 + 9 + 9 = 19 → 1 + 9 = 10 → 1 + 0 = 1 which is not
divisible by 9, so 199 is not divisible by 9.
1125: 1 + 1 + 2 + 5 = 9 which is divisible by 9, so 1125 is
divisible by 9.
So 199 is the only one not divisible by 9.