Rule:

Subtract by:

If second digit < first digit: [second digit * 11 * 1X] If first digit < second digit: [first digit * 11 * 1X] where, in both cases, X is one zero for each of the N-2 digits there are in the number and repeat the process until you get to a number less than 11. If it is 0, the original number is divisible by 11. Example: 159963 Subtract by 110000 159963 - 110000 = 49963 Subtract by 44000 49963 - 44000 = 5963 Subtract by 5500 5963 - 5500 = 463 Subtract by 440 463 - 440 = 23 Subtract by 22 23 - 22 = 1 1 is not divisible by 11 so 159963 is not divisible by 11. Another example: 9856 Subtract by 8800 9856 - 8800 = 1056 Subtract by 990 1056 - 990 = 66 Subtract by 66 66 - 66 = 0 So 9856 is divisible by 11.