Big Ideas:
Real world situations can be represented by mathematical expressions.
Variables are used to represent unknown information.
Numbers can be substituted for variables to determine hypothetical values.
This lesson builds on representing real-life situations with single step expressions by asking students to develop two-step expressions. In this task, students write two-step expressions that represent the profit that could be made by selling an item at a food sale. They are then asked which item they believe would be most profitable. Students conceptualize that there is more than one possible answer because estimating how many of each item may get sold is open to interpretation. While there is no correct answer to this task, students must demonstrate that they have accurately built expressions and can use words, diagrams, and calculations to support their assertions. This concept builds toward the skill of solving for variables in real-life situations.
Vocabulary: expression, variable, profit, substitute
Lesson plan