Question

Explain why 186,426 is divisible by both 3 and 9.

Answer 1

We will use divisibility criteria.

1. Divisibility criteria for 3 : a natural number is divisible by 3 if the sum of its digits is a multiple of 3.
2. Divisibility criteria for 9 : a natural number is divisible by 9 if the sum of its digits is a multiple of 9

So, to find out if 186,426 is divisible by both 3 and 9, we first compute the sum of its digits. We have

`1 + 8 +6 +4 +2 +6 = 27`

Given that 27 is a multiple of 3 and 9, we conclude that 186,426 is divisible by both 3 and 9.