The purpose of this lesson is for students to practice addition and subtraction within 100 that does not require composing or decomposing a ten.

This lesson is optional because it is an opportunity for extra practice that not all classes may need. Students learn new stages of centers that were introduced in grade 1. In the first activity, students learn Stage 3 of the Capture Squares center. In this new stage, called Add within 20, students find the value of sums within 20. In the second activity, students learn Stage 6 of the Five in a Row center. In this stage, students practice finding the value of sums within 100 that require composing when adding by place.

Identify ways the math community you are working to foster is going well. What aspects would you like to work on? What actions can you take to improve those areas?