Consider a 3-digit number and reverse its digits. Find the difference between original and reversed number. By what numbers this difference is divisible? Select all that apply.
9
11
99
Suppose abc be a 3-digit number.
Original number = 100a + 10b + c
Reversed number 100c + 10b + a
Difference = 100a + 10b + c - 100c - 10b - a
= 99a - 99c = 99(a - c)
The difference is divisible by 3, 9, 11, 33 and 99