# 2.NBT.9 Second Grade Common Core Lesson

In this 2.NBT.9 Second Grade Common Core lesson, students Explain why addition and subtraction strategies work, using place value and the properties of operations. First, students will create their own addition and subtraction problems. Then, draw a picture, and explain why the strategies work. Continue your practice using the provided worksheet individually or with a partner.

### Teacher Directions for 2.NBT.9 Second Grade Common Core Lesson

This 2.NBT.9 Second Grade Common Core lesson gives students an opportunity to practice more with Addition and Subtraction properties. This lesson is perfect for small group, math centers or independent practice. You may introduce this lesson by presenting an equation and asking students to solve in anyway that they choose. When choosing students to share out, be sure to choose students that are using base ten and property strategies. Then, pass out addition and subtraction work mats. As students work, circulate around the classroom to listen to discussions students have about different ways they can solve the problem.  After the activity, share students discussions that you heard to promote addition and subtraction skills. Finally, students continue their practice using the provided worksheet.  Be sure to check out more Addition and Subtraction activities and the entire Second Grade Common Core workbook.