Lesson objective: Solve problems by finding combinations of two numbers one through nine that equal 10.

This lesson provides an opportunity for students to apply their knowledge and understanding of composing and decomposing numbers to a real-life situation. Students are asked to identify the total number of possible combinations of 10 frogs located with some on a pond and some in the grass.

Key Concept students will use:

Skills students will use:

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

Students engage in Mathematical Practice 8 (Look for and express regularity in repeated reasoning) as they analyze patterns to find all of the combinations that make 10.

**Key vocabulary: **

- combinations
- compose
- decompose
- make a 10
- number bond
- number partner
- total

**Special materials needed:**

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