In this lesson, students build on their understanding of tens as they add 10 and subtract 10 from multiples of 10. Students learn to think of adding or subtracting 10 as adding or subtracting a ten from a number of other tens. In the first activity, students use towers of 10 to physically add or subtract a ten from a multiple of 10. In the second activity, students learn a new stage of the Five in a Row center. Students choose a card with a multiple of 10 and decide whether to add or subtract 10. The goal is to cover five spaces in a row on their gameboard. They can continue to use towers of 10 if helpful.

Reflect on times you observed students listening to one another’s ideas today in class. What norms would help each student better attend to their classmates’ ideas in future lessons?