Learning Intention: Students will be able to add two-digit numbers within 20.

Objective: Students will be able to solve addition equations with two-digit numbers within 20, both with and without regrouping.

Materials Needed: Whiteboards and whiteboard markers, a projector, a worksheet of two-digit addition problems

Warm-up: To get students familiar with addition and make it a fun activity, invite students to play a game of flash cards. Provide students with cards that have two two-digit numbers on it and have them respond to which number is larger.

Introduction: Explain to students that they will be working on two-digit addition, which involves carrying and regrouping.

Lesson:

1. Model solving an equation with regrouping on the board. Begin by solving 17 + 8. Model what it looks like to regroup and carry the “10” over to the ones column, so students can clearly understand the concept of regrouping.

2. Provide students with whiteboards and have them independently solve an equation with regrouping, such as 14 + 9. Have students show their work on their whiteboards and explain their thinking.

3. Ask students to look at the worksheet and identify if any of the equations involve regrouping. Solve an equation on the board, such as 19 + 1.

4. Ask students to work with a partner to solve the remaining equations on the worksheet. Ask them to explain their thought process to one another, explaining the concept and how they come to their answer.

Conclusion: Lead a discussion about the problems students were working on and review how to solve equations that involve regrouping.

Assessment: Assess student understanding by having students work independently on a final two-digit addition equation that involves regrouping.