I have a pile of sweets which contains less than 30 sweets.  If I put them into piles of 3, I have none left over.  If I put them into piles of 2, 4 or 5, I always have one left over.  How many sweets do I have? 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Whole Numbers Multiplication and Division->Division of Whole Numbers->Division with Remainders