How do you know if a number is divisible by 3?

Answer - How do you tell if a number is divisible by 3?

you add all the digits in the number and see if that number can be divided by 3 Answer - A whole number is divisible by 3 if the sum of its digits is divisible by what?

Three (3) Examples:

* 27 -- 2+7=9 * 13452 -- 1+3+4+5+2=15 -- 1+5=6
If the sum of the digits is divisible by 3, the number is also divisible by 3. Or just do the division.