Question

Using the divisibility test, determine $121$ is divisible by $11$ or not?

Answer 1

Divisibility of $11$: A number is divisible by $11$, if the difference between the sum of the digits of the number at even places and the sum of the digits of the number at odd places(starting from the ones place) is divisible by$11$, or $0$.

Consider the number $121$

Sum of the digit at odd places = $1+1=2$

Sum of the digit at even places = $2$

The difference = $2-2=0$

Then, the number $121$is divisible by $11$ .

Thus, $121÷11=11$