Title : Applying Fraction Multiplication and Division to Recipes

Grade Level : 6 and up

Approximate duration time : 45 minutes

Goal Statements : In this lesson, students use recipes to practice their fraction multiplication and division skills by calculating the amounts of ingredients needed to make specific recipes. Students will also use these fraction skills to convert small units of cooking measures to larger units.

Objectives : Students will :

1. 1. Apply fraction multiplication and division skills to calculate the amounts of

ingredients needed to make specific recipes, given varied numbers for the ‘yield’ quantity.

2. Convert small units of cooking measures to larger units.

Materials :

Procedures :

1. Write the following word problem on the board for students to solve in the first few minutes of class:

"Your class has volunteered to bake sugar cookies for a school bake sale. The recipe that you will use yields two dozen cookies and calls for the following ingredients:

• 1 cup white sugar
• 1 cup butter or margarine
• 2 eggs
• 3 ½ cups sifted all-purpose flour
• 2 teaspoons baking powder
• 2 teaspoons vanilla extract

Calculate how much of each ingredient you will need to bake 60 sugar cookies."

1. After about five minutes, students are asked to share their problem-solving techniques. Students should have determined that the ingredients should be multiplied by 2 ½ (5/2 or 2.5), since the original recipe yields two dozen cookies (24), and they are planning to bake five dozen cookies.
2. Students should calculate that they would need 2 ½ cups of sugar, 2 ½ cups of butter or margarine, 5 eggs, 8 ¾ cups of flour, 5 teaspoons of baking powder and 5 teaspoons vanilla extract.
3. Students now are challenged to calculate the amount of ingredients if they wanted to bake only 6 cookies. (Divide the recipe by four if using original recipe or by 10 if using recipe for 60 cookies).
4. Again students are asked to share their problem-solving techniques. Students should calculate that they will need ¼ cup of sugar, ¼ cup of butter or margarine, ½ egg, 7/8 cup of flour, ½ teaspoon baking powder and ½ teaspoon vanilla extract.
5. Questions for Discussion:

• What are the steps for multiplying fractions?
• What are the steps for dividing fractions?
• What ‘mathematics’ exist in cooking?
• In what daily situations do people use fractions to help them solve problems?

1. Assessment/evaluation procedures:

• Students will be evaluated based on answers for fraction multiplication and division problems.
• Homework (as an extension activity): Select a recipe from The Miami Herald’s Thursday Food section. It always contains recipes that can be used by students to practice fraction multiplication and division or measurement conversions. Find out (may visit a grocery store/market) how much each ingredient costs. Figure out how much it would cost to make this recipe for your entire family based on these calculations.