Question

Explain the divisibility rule for division by 11 with an example.

Answer 1

Let's find the sum of the digits in the even places of the given number and the sum of the digits in its odd places. If the differences between the two sums is 0 or a multiple of 11, then the given number is divisible by 11.

E.g., let's consider the number as 72512.

Sum of its digits at even places = 2 + 1 = 3
Sum of its digits at odd places = 7 + 5 + 2 = 14

The difference between the two sums = 14 - 3 = 11; which is a multiple of 11

$\therefore$ 72512 is divisible by 11.

In the same way, each of 957, 1496, 68772 is divisible by 11.