How do you solve this problem? There are less than 1,000 tennis balls to be packed in boxes: whether they are packed by 4's, or 5's or 6's or 8's, there will always be 1 left out. How many tennis balls are there altogether? We need to use the least common multiple to solve the problem. The 50 problems in this book teach you step by step how to use the greatest common factors and the least common multiples to solve word problems . This is volume 1 of the entire set. If you need more similar problems to work on, please find volume 2 in Amazon. com to find the same title or go to www.amathproblem.com to find volume 2 in books by the author of the blogs.