Use divisibility rules, prime factorization, and factor structure to analyze and solve whole-number problems.
Check divisibility with one rule
Problem
Is \(342\) divisible by \(3\)?
Big Picture
What this problem is really about
The rule for divisibility by three turns a large division problem into a digit-sum check. We’ll add the digits of three hundred forty-two, test whether that sum is divisible by three, and use the result to classify the original number. This works because a number and its digit sum have the same remainder when divided by three.
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