Meal Deal
Math Lesson ("Systems of Equations")

Contributed by Julie Poth: Elementary Science TSA
Pinellas County School District, Largo, FL

 Materials * Handout: Meal Deal Math Standards

Overview: Students look at the total costs of rows and columns of whooping crane food items and figure out how much each food item costs.

Teacher Background
Students will explore logical reasoning using unknowns in studying systems of equations. Students will use logical thinking instead of guessing, checking, and revising.

Activity

1. Pass out the Meal Deal handout (1 per student). Also make a transparency of it to use on an overhead projector. Each of the 9 squares on the handout contains a picture of a meal worm, bowl of crane chow, or bunch of berries, all of which are part of the Whooping Crane diet.
Note: The project costs are not actual costs. They were adapted so the numbers were manageable for students.
2. Show the students that the total costs for each row or column is recorded at the end of each column and row.
3. Explain that each food item: meal worms, crane chow, and berries -- costs a specific amount of money. Their goal is to look at the rows and columns and figure out how much each of the food item costs.
4. Ask the students to look at the rows and columns and put an X on the one row or one column they think would be the easiest to use to figure the cost of one food item. Ask them to explain why they chose the ones they did.
5. Students will most likely identify row 3 with the three crane chows. Since the total cost for three crane chows is \$15, each crane chow must cost \$5. 3 x ? = 15. If the students can’t explain this, guide them to that understanding.
6. The students now have a piece of the puzzle to begin solving a system of equations: They know that the crane chow cost \$5. Ask, How can you use this information to determine the cost of the meal worms or berries?
7. Walk around the room to observe how the students are solving each element. When they have determined the cost of the meal worms and the berries, ask them to explain how they did so. After one student identifies how he or she solved the problem, ask if anyone used another method.

Extension
Have the students design their own 3 x 3 Square Systems of Equations.

Assessment
Meal Deal handout; teacher questions and observations