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

Materials: - Dedicated work space - Pencil and paper (one sheet per student) - Number tiles or counters (enough for each student to have 10)

Warm-Up: Have students stand up and clap out numbers from 1 to 20.

Introduction: Inform students that today we are going to practice adding 2-digit numbers within 20. Explain to students that adding is simply combining two or more numbers to make a larger number.

Main Activity: 1. Give each student a sheet of paper, a pencil, and 10 number tiles or counters. 2. Demonstrate how to begin adding numbers by using the number tiles or counters. For example, “If I am adding 9 + 8, I would put 9 tiles or counters on the table, and then 8 more tiles or counters on the table”. 3. Have each student pick two 2-digit numbers within 20. They should write their two numbers on the paper. 4. Have students count out the amount of tiles or counters for each number and place them next to each other in one row. 5. Then have them count how many tiles or counters are altogether. 6. Once students understand the idea of counting the whole group of tiles or counters, have them write the number sentence (i.e. 9 + 8 = 17) on their paper. 7. Repeat process with additional two-digit numbers. 8. When all students have completed the activity, discuss answers with the class.

Conclusion: Evaluate students’ understanding of the activity. Ask questions such as “What did we do today? How did we add two-digit numbers within 20? How can you use this knowledge in everyday life?”.

Assessment: Observe student participation and level of understanding during activity.