Question

disability rule of 11

Answer 1

If that is divisible by 11, so is the original number. So, for instance, 2728 has alternating sum of digits 2-7+2-8 = -11. Since -11 is divisible by 11, so is 2728. Similarly, for 31415, the alternating sum of digits is 3-1+4-1+5 = 10.

Answer 2

Disability rule of 11
Form the alternating sum of the digits. The result must be divisible by 11.[1][4]
Add the digits in blocks of two from right to left. The result must be divisible by 11.[1]
Add the last digit to the hundredth place (add 10 times the last digit to the rest). The result must be divisible by 11.