Lesson objective: Solve problems involving addition and subtraction of whole numbers within 20.

This lesson provides an opportunity for students to apply their knowledge and understanding of addition and subtraction to a real-life situation. Students are asked to use a table listing bags of jelly beans and the number in each bag to solve addition and subtraction problems. This task is designed to engage students in making sense of problems and requires students to engage in multiple operations. If you feel this lesson moves too quickly for your students, adjust the lesson time to multiple days, or eliminate some of the problems on the student sheet for some students, as needed.

Key Concept students will use:

- We can count on or make ten to add and subtract within 20, and the total or difference stays the same regardless of the strategy we use.

Skills students will use:

- Compose and decompose numbers within 10. (K.OA.10 - Kindergarten, Units 10 and 16)
- Read and write numbers to 20. (K.CC.1 - Kindergarten Units 2 and 7)
- Find the sum of single digit numbers to 10. (K.OA.4 - Kindergarten, Units 4, 6, 10, and 16)
- Count on to 100 from a number other than 1. (K.CC.2 - Kindergarten, Unit 14)
- Add and subtract within 10. (K.OA.2 - Kindergarten, Unit 10)

Students engage in Mathematical Practice 1 (Students** **make sense of problems and persevere in solving them) as they examine a table and decide on the quantity of jelly beans to use to complete and solve additional and subtraction word problems.

**Key vocabulary: **

- add
- equals
- makes
- problem
- solve
- subtract

**Special materials needed:**

- counters or linking cubes