This lesson builds on the previous lesson as students were asked to determine the sum of two numbers represented by dot cubes. It also builds on the work of kindergarten, where students wrote addition expressions to represent images and situations. In this lesson, students match expressions to dot images before they are asked to write addition expressions (MP2). Students also continue to build their math language related to the sums, addition expressions, and mathematical community (MP6). Note that students are introduced to the term “sum” in the second activity.

Math Community
Tell students they will have a chance to revise their math community ideas at the end of this lesson. As students work today, they should think about actions that may be missing from the current list.