Lesson objective: Apply knowledge of counting, one more, and addition to solve a problem.

This lesson provides an opportunity for students to apply their knowledge and understanding of one-to-one counting, the concept of "one more," and addition as combining quantities to a real-life situation. Students are asked to help two characters figure out who won the game by finding an unknown addend.

Key Concept students will use:

- the concept that addition can be understood as adding to a group

Skills students will use:

- adding by putting groups together
- counting one-to-one (Grade K, Unit 1)
- finding one more than a given set

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they use multiple skills to find a missing addend and find the answer to a multi-step problem.

**Key vocabulary: **

- add to
- addition
- change
- count
- zero

**Special materials needed:**

- counters or other manipulatives