This document is a complete lesson, which includes warm-up, opening, work time, closing, and extra practice. It includes properties of addition and how/why they don’t apply to subtraction and computation with a focus on problem solving based on the Common Core Standards. The interactive lesson was created with Notebook software and includes 11 slides. Also included is a lesson outline/plan as well as an explanation slide for using features in the lesson such as "reveal" and "hint" objects. Although created based on the fifth grade Common Core Standard 5.NBT.7, this lesson could be used in other grade levels where decimals are taught and/or practiced. While it is a single lesson, it may take more than one day especially if the extra practice slide is used as a follow-up lessons. Slides may be printed as well.