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

Materials: -Whiteboard -Whiteboard markers -Individual student whiteboards -Individual student whiteboard markers

Objective: By the end of the lesson, students will be able to add two two-digit numbers within 20 using the traditional add the column method.

Procedure:

1. Introduction (10 minutes) -Discuss why it is important to know how to add two digit numbers within 20, and what kinds of situations we may encounter where this skill will be useful (grocery shopping, budgeting, etc)

2. Addition Activity (15 minutes) -Provide students with whiteboards and markers, and ask them to work together to break down a two-digit number (e.g. 15 + 17) into 1s and 10s (5 + 7 and 10 + 10). -Have the students write down the solution on their whiteboards, and then show the answer to the class. -If the answer is incorrect, provide guidance by helping them to break down the numbers and model the correct answer.

3. Conclusion (5 minutes) -Discuss with the class how they were able to use the traditional column method to solve the problem, and how they can use this same method for other two-digit numbers within 20.

Assessment: -Observe students’ work and provide feedback; -Have students explain their thinking and strategies for solving the problem.