This lesson is optional. It repeats some of the ideas of Lesson 2 and can be used for additional practice on the concept of unitizing a group of ten.

Lesson objective: To practice making a bundle of 10 ones and recognizing that bundle as one group of 10.

This lesson helps to build procedural skill with place value. A ten frame is used here because it represents 10 single ones bundled into one unit of 10. This work develops students' understanding that the one in the tens place of a teen number is equal to one group of 10.

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they represent bundles of 10 both pictorially and numerically in a ten frame and on a number path.

**Key vocabulary:**

- bundle
- frame
- group
- ones
- singles
- Ten

**Special materials needed:**

- counters
- 1- 9 numeral cards