Lesson objective: Solve real-world problems using the distributive property with algebraic expressions.

This lesson provides an opportunity for students to apply their knowledge and understanding of the distributive property to a real-life situation. Students are asked to write algebraic expressions describing the number of pieces of food Mrs. Hall feeds her cat in five days, ten days, 30 days, and then select the best size bag of food to buy.

Key Concept students will use:

- The distributive property applies to algebraic expressions just as it does to numeric expressions.

Skills students will use:

- Order of operations to evaluate expressions (Grade 5, Unit 13).
- Write an expression describing a real-world situation (Grade 5, Unit 13).
- Evaluate an expression at a given value of the variable.

Students engage in Mathematical Practice 7 (look for and make use of structure) as they determine how to write an expression describing the food eaten in one day and then modify the expression to write expressions describing the food consumption for multiple days. Pictures allow students to see that the food eaten in one day is a group just as the expression representing one day's food is a group.

**Key vocabulary: **

- distributive property
- expression
- factor
- order of operations