Lesson 4

The purpose of this lesson is to build toward fluency within 10 by looking for and making use of patterns in sums that have a value of 10.

In a previous lesson, students found different expressions with the same value. In this lesson, students write different expressions that equal 10. They try to find all of the ways to decompose 10. Knowing all decompositions of 10 will be helpful later when students add and subtract within 20. For example, when students find the sum of \(9 + 5\), they can decompose 5 into 1 and 4 to make a ten (\(9 + 5 = 9 + 1 + 4 = 10 + 4\).) In the first activity, students play Shake and Spill to identify expressions that equal 10. In the second activity, students find all the ways to make 10 and share how they know they found all of the ways.

• Gather materials from previous centers:
  • Number Puzzles, Stage 1
  • Check It Off, Stages 1 and 2
  • Find the Pair, Stage 2

Reflect on how easily students found different ways to make 10 and which ways they know from memory. How prepared are students to make 10 in order to add within 20 in an upcoming section. In what other ways can you offer practice that will help prepare students for this work.