Answers

2015-12-12T09:39:03+08:00
Let's start from 999 (largest three-digit number)
Since 999 is divisible by 9 (obviously) etc. It can't be.
          998 is an even number so divisible by 2 and etc. so It can't be.
          997 is a prime number.

Therefore, the answer to your question is 997.
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