Question

Use the divisibility tests to determine whether the following numbers are divisible by 2, 3, 4, 5, 6, 9 or 11.

(3) 711

Answer 1

We can observe that the sum of the digits 7, 1 and 1 is 9, which is divisible by both 3 and 9.
If the sum of all the digits in a number is divisible by 3 and 9, then the number is divisible by 3 and 9. So, the number 711 is divisible by both 3 and 9.