About This Lesson
This is the fourth and final lesson from the unit "Addition and Subtraction Strategies." In this lesson, explain to students that a fact family is a set of facts that use the same numbers. For example, 9 + 1 = 10 and 1 + 9 = 10 are in the same fact family. Related facts are number sentences that use the same set of numbers with inverse operations: 10 – 1 = 9 and 10 – 9 = 1. The equations use the same numbers, but with different operations; they are part of the same fact family as well. Aligned to Common Core State Standard: 2.OA.2
