Lesson objective: Apply knowledge of addition and subtraction to create two expressions that have the same value.

This lesson provides an opportunity for students to apply their knowledge and understanding of addition and subtraction to a mathematical situation. Students are asked to create two equal expressions from four different numbers, using each number only once.

Key Concept students will use:

- The equal sign imeans that the expressions on either side have the same value.

Skills students will use:

- Apply properties of operations as strategies to add and subtract (Grade 1, Unit 6)
- Understand subtraction as an unknown-addend problem (Grade 1, Unit 6)

Students engage in Mathematical Practice 4 (model with mathematics) as they manipulate numbers to create equivalent expressions.

**Key vocabulary: **

- equal
- equation
- equivalent
- expressions