WARM UP 8/28Change these mixed numbers to

improper fractions.

Lesson Check Up

Multiply or Divide the Fractions Below

Lesson Objective: To solve math problems involving division of fractions.

Today, we will use…• visual fraction models • division equations

Dividing Fractions

• What does 4 ÷ 2 mean in words? Justify your reasoning by using a model or a drawing.

how many groups of 2 are in 4?

÷

There are 2 groups of 2 in 4, therefore

4 ÷ 2 = 2

Example 1

• What does 3/4 ÷ 2/3 mean in words?

(How many groups of 2/3 are in 3/4)?

Example 13/4 ÷ 2/3

• When dividing fractions…

Model the first fraction.

÷

Model the second fraction.

Example 13/4 ÷ 2/3

• Next, divide both models into the same number of pieces… In this case it would be 12 pieces.

The # I have!

÷

The # I want!

9 = 1 1 8 8

Example 13/4 ÷ 2/3

• Next, find out how many groups of 2 /3 are in 3/ 4.

The # I have!

÷

The # I want!

9 = 1 1 8 8

There is 1 whole group of 8 and one more left out of another group of 8

Example 2Mrs. Watkins is cutting trim for her windows. She has 1/2 yard of trim and she needs to cut her trim into pieces that are 1/3 yard pieces. How many

pieces of trim can she cut?

1/2 ÷ 1/3

÷

1/31/2

Model the first fraction. Model the second fraction.

Example 2

1/2 ÷ 1/3

÷

1/31/2

• Next, divide both models into the same number of pieces… In this case it would be ___ pieces.

3 = 1 1 2 2

6

Example 2

1/2 ÷ 1/3

÷

• Next, find out how many groups of 1 /3 are in 1/ 2.

The # I have! The # I want!

3 = 1 1 2 2

She can cut 1 whole piece and one piece that is only half as long as she needs.

Example 3

Mr. Shannon is making a cake for Labor Day. He needs 1 2/3 cups of flour

but his measuring cup only measures ¾ of a cup. How many ¾ cup portions of flour will he need to

put into the recipe?

1 2 ÷ 3 3 4

÷

Model the first fraction or mixed number.

Model the second fraction.

Example 3

1 2 ÷ 3 3 4

÷

• Next, divide both models into the same number of pieces… In this case it would be ___ pieces.12

Example 3

1 2 ÷ 3 3 4

÷

20 = 2 2 9 9

Example 3

1 2 ÷ 3 3 4

÷

20 = 2 2 9 9

Find out how many groups of 3/4 (9 units)

are in 1 2/3 (20 units)

Mr. Shannon will need 2 whole portions out of his measuring cup plus 2/9’s more.

Guided PracticeSOLVE by using the S.O.A.R. method or

by making area models.

1. 1/2 ÷ 1/4

2. 1/2 ÷ 2/3

3. 2/3 ÷ 1 /2

4. 2/3 ÷ 1/4