Lesson objective: Apply the knowledge of addition with three addends.

This lesson provides an opportunity for students to apply their knowledge and understanding of solving problems that involve addition of three addends to a real-world situation. Students are asked to help plan a community garden by selecting three different types of plants and the numbers of each plant type to put in the garden.

Key Concept students will use:

- We can add more than two numbers together.

Skills students will use:

- Solving addition and subtraction word problems within 10 (Grade K, Unit 6)
- Compose and decompose numbers less than or equal to 10 (Grade K, Unit 6)

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they look for the structure in a number to find a way to decompose it into three smaller numbers to find three missing addends.

**Key vocabulary: **

**addends: **one of the numbers in an indicated sum of two or more numbers (e.g., 4 + 3 + 1 = 8; 4, 3, and 1 are addends)
**addition: **a mathematical operation of combining two or more numbers into a total or sum
**decompose: **to break a number into smaller units to simplify computation
**sum: **the result when two or more quantities are added
**total: **the whole amount or value

**Special materials needed:**

- linking cubes
- number lines (0-20)
- ten frames