This Problem Set is a part of the Lesson 22, Unit 1, Grade 1. In this lesson, students explore patterns among familiar facts on the addition chart. They look for common addends and discuss how those addends affect the total in systematic ways. For example, given the sequence 3 + 2 = 5, 4 + 2 = 6, 5 + 2 = 7, and 6 + 2 = 8, which forms part of a row in the addition chart, they notice that the totals increase by 1, because the first addend is 1 more each time.
