Lesson objective: Solve problems that require you to find the one number that partners with another number one through nine to make 10.

This lesson provides an opportunity for students to apply their knowledge and understanding of composing 10 to a real-life situation. Students are asked to determine the number of bowling pins that have been knocked over using the number of bowling pins that are left standing.

Key Concept students will use:

Skills students will use:

- Counting objects (Kindergarten, Unit 2)
- Understanding addition as putting together (Kindergarten, Unit 4)
- Decomposing objects in multiple ways (Kindergarten, Unit 10)

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they notice that there is only one number that is added to each number one to nine that will make 10. The ability to make 10 is also foundational to place value understanding.

**Key vocabulary: **

- compose
- decompose
- number bond
- put together
- 10-frame

**Special materials needed:**

- 10-frames, 10-strips or 10 two-sided counters are optional and may be needed by some students