How do you know if a number is divisible by three?
Example: 123. You add all the numbers together: 1 + 2 + 3=6. If 6 is divisible by 3(which it is), then the whole number 123 is divisible by 3. Try it.
If the digits in the number add up and the answer is divisible by 3, than the number is divisible by 3.
