Lesson 5-4

Solving Fraction Equations: Multiplication and Division

Warm Up (4 minutes)

Student Will Be Able ToSWBAT/Definitions

• SWBAT solve equations by multiplying & dividing. pp. 226-229

• Definition– Reciprocal

• Two numbers are reciprocals if their product is 1.• Example: Numbers 1/5 and 5 are reciprocals and their

product is 1/5 ● 5 = 1

Skill Set – Solving Math Equations

r = 12Reciprocal of isMultiply both sides by the reciprocal

1644;3

412

4

3

3

4 rr

4

34

3

3

4

7

23 t

95

3r

7

1

7

1a

1

4

4

a

Skill Set – Solving Word Problems

• Problem 1: Dexter makes dog biscuits for the animal shelter. He makes of a recipe and uses 15 cups of powdered milk. How many cups of powdered milk are in the recipe?

• Problem 2. A recipe for a loaf of bread calls for cup of oatmeal. How much oatmeal do you need if you double the recipe?

Problem 1: Dexter makes dog biscuits for the animal shelter. He makes of a recipe and uses 15 cups of powdered milk. How many cups of powdered milk are in the recipe?

Step 1. Read the problem.

Step 2 Identify the variable(s) – Who and What

Cups of Powdered Milk:

Step 3. Draw the unit bar (powdered milk in the whole recipe)Step 4. Reread the question and adjust the unit bar.Step 5. Annotate the question, "How many cups of powdered milk are in the recipe?Step 6. Do the computation.

15 cups

?

1 unit = ? 1 unit = 20 cups

Step 7. Write a grammatically correct sentence. "The dog biscuit recipe has 20 cups of powdered milk."

Problem 2. A recipe for a loaf of bread calls for cup of oatmeal. How much oatmeal do you need if you double the recipe?

Step 1. Read the problem.

Step 2 Identify the variable(s) – Who and What

Double recipe’s cups of oatmeal:

Step 3. Draw the unit bar (cup of oatmeal in recipe)Step 4. Reread the question and adjust the unit bar.Step 5. Annotate the question, "How many cups of oatmeal if the recipe is doubled?Step 6. Do the computation.

15 cups

?

2 units = ?2 unit = cups

Step 7. Write a grammatically correct sentence. "The bread recipe has cups of oatmeal."

4

3

Recipe’s cups of oatmeal: 4

3

4

31 unit

2

11

4

21

4

6

4

322 units

2

11

2

11

Lesson Assessment