Lesson objective: Understand that grouping symbols sometimes change the value of an expression, but not always.

Students bring prior knowledge of solving problems with the four operations from 4.OA.OA.3, 5.NBT.B.5, and 5.NBT.B.6. This prior knowledge is extended to evaluating expressions with parentheses as students discover whether or not parentheses will change the value of an expression. A conceptual challenge students may encounter is coming up with new expressions that have the same value.

The concept is developed through work with a two-column chart, which helps students to organize their thinking as they write out each step while evaluating.

This work helps students deepen their understanding of equivalence because the same expressions written with or without parentheses can be equivalent to each other.

Students engage in Mathematical Practice 6 (attend to precision) as they use the order of operations and a two column chart to efficiently and accurately evaluate expressions.

**Key vocabulary:**

- equivalent
- evaluate
- numerical expressions
- order of operations

**Special materials needed:**

- highlighter
- order of operations chart