Question

Which of the following helps you to determine that three hundred sixty-nine is divisible by 3?

The first digit is a 3.

9 is divisible by 3.

sixty-nine is divisible by 3.

3 plus 6 plus 9 is divisible by 3.

Answer 1

The last one. To find out if a number is divisible by 3, add the digits that make up the number. It the sum of the digits is divisible by 3, the original number is divisible by 3.

Answer 2

The digits sum to sum to 9 which means divisible by 9 and therefore divisible by 3

Answer 3

The digits sum to 18 actually. And 18 is divisible by 3 because 3 x 6 = 18.
So 369 is divisible by 3 too!