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

Materials: - 10 two sided counters for each student - Worksheet - Dry erase markers

Lesson:

1. Begin the lesson by introducing the concept of adding two digit numbers within 20. Make sure students understand that the addition of two digit numbers is the same as adding tens and ones. Emphasize that they are using tens and ones units to add the numbers.

2. Instruct students to form pairs and give each student 10 two sided counters. Ask the pairs to represent any two digit number within 20 using the counters, e.g. 19 can be represented as 10 red counters and 9 blue counters. They should practice doing this several times.

3. Call the class back to whole group and discuss the adding of two digit numbers. Explain that each counter represents 10 and 1, so adding the two digit numbers is a matter of combining the tens and ones.

4. Pass out the worksheet with a variety of two digit numbers and have students work in pairs to solve the equations. For example, 8 + 11 = 19 (8 + 10 = 18 and 18 + 1 = 19).

5. Go through the answers together as a class and use the counters to show how to solve the problem (e.g. by forming 8 red and 11 blue counters).

6. Give students extra practice if needed by having them draw a ten frame and then fill it in with two digit numbers and have them add them.

7. As a closing activity, have students write a sentence about what they learned about adding two digit numbers.