Objective: Students will add two digit numbers within 20.

1. Watch a brief instructional video that explains how to add two-digit numbers within 20.

2. Have the students practice in their notebooks by solving several problems (e.g. 11 + 11, 19 + 2, 18 + 4, etc.).

3. Give the students several group problem solving practice problems. Students can work in pairs or in small groups to solve the problems.

4. Once the students have mastered the addition of two-digit numbers within 20, allow them to work on a self-paced activity where they solve two-digit addition problems within 20, as quickly and accurately as possible.

5. Give a short assessment at the end of the lesson to see how well the students are retaining the information.

6. Wrap up the lesson by reviewing the main points of addition for two-digit numbers within 20 and answer any remaining questions.