In general, we know that if the sum of dights of a number is divisible by 3, then the number is divisible by 3.For example, 324 ,i.e. 3+2+4 =9 9/3=3, so 324 is divisible by 3. how to prove this?

Using mathematical induction or other methods.

In general, we know that if the sum of dights of a number is divisible by 3, then the number is divisible by 3.For example, 324 ,i.e. 3+2+4 =9 9/3=3, so 324 is divisible by 3. how to prove this?

Using mathematical induction or other methods.