Students practice finding the missing part with groups of up to 5 objects in the first activity. In the second activity, students fill in equations with an unknown value that all equal the same number. The second activity is optional, because determining the unknown value of an equation is not required by the kindergarten standards.

If students need additional support with the concepts in this lesson, refer back to Unit 5, Section A in the curriculum materials.

Given one part, how do students find the other part to make 5? How do students explain how they found the missing part?