If the number 632y513 is completely divisible by 3, what is the smallest whole number in the place of y?
If a number is divisible by 3, the sum of the digit of the number must be divisible by 3. ⇒ (6 + 3 + 2 + y + 5 + 1 + 3) must be divisible by 3 ⇒ (20 + y) must be divisible by 3. The minimum value of y for it to be true is y = 1.