Lesson objective: Solve problems by taking apart.

This lesson provides an opportunity for students to apply their knowledge and understanding of decomposition to a real-life situation. Students are asked to create at least two combinations of tomato plants and pea plants to fill Ms. Aziz's five new pots. Students decompose five using counters, drawings, or five frames while exploring whether organizing their combinations can prove that each way produces a unique combination or set of number partners.

Key Concept students will use:

- Subtraction can be understood as taking apart.

Skills students will use:

- Counting one-to-one and counting to tell "how many" (Grade K, Unit 1).
- Understanding that arrangement or order of objects does not affect the total in a set (Grade K, Unit 2).
- Decomposing a set with concrete objects to model.
- Constructing equations to quantify each part of set.

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they decide which combinations of each plant to fill the five new pots. If each type of plant is grouped together, students may find it easier to compare their combinations and determine if each number partner is a unique set.

**Key vocabulary: **

- number partners
- subtraction
- take apart

**Special materials needed:**

- counters
- five frames
- record sheet (or another option to record thinking)