Question

How can you tell if a number is divisible by 3? 

A. The last number is 3.   B. The sum of the digits of the number is a multiple of 3.   C. The first two digits are divisible by 3.   D. The number ends in an odd digit.

Answer 1

B is correct. Also, if you have a number such as 876543 and add the digits, it is 33. If you did not know this was divisible by three, you could add 3+3 and get 6, which is divisible by three, making 876543 divisible by three.

Answer 2

The correct answer is B. Try it out with the following number: 312, 1893, 255, 344, 232. Two of the or not divisible by 3 by the way.