Adding & Subtracting Expressions & Properties in a PowerPoint PresentationThis slideshow lesson is very animated with a flow-through technique. It was made for my Algebra 1 class, but can be used for lower grades. This lesson was one of a chapter that was used as a review for all previous grades. The lesson teaches how to add and subtract expressions by combining like terms and a review of properties (Commutative, Associative, Identity, & Distributive).NEW: The lesson is in an edita