For a complete lesson on decimal word problems, go to http://www.MathHelp.com – 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson, students learn to solve word problems that involve adding or subtracting decimals. For example: Margaret is mailing three letters that weigh 3.7 oz., 2.913 oz., and 2.82 oz. What is the combined weight of the letters?