Answer: Show that a positive integer is divisible by 3 if
Chapter 3, Problem 3.6.29(choose chapter or problem)
Show that a positive integer is divisible by 3 if and only if the sum of its decimal digits is divisible by 3.
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer