Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
2
Warm Up What is of each of the following?
1. 24 2. 16 3. 30 4. 28
12
8
14
15
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Problem of the Day At midnight Caitlin heard a
forecaster say that it would be cloudy for
exactly 72 hours and then would be sunny. Caitlin
knew the forecaster was wrong. Explain.
There are 24 hours in a day, so 72 hours equals 3
days. In 3 days it would be midnight again, not
sunny.
4
Learn to multiply fractions and mixed numbers.
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To multiply fractions, multiply the numerators
to find the products numerator. Then multiply
the denominators to find the products denominato
r.
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Additional Example 1A Multiplying Fractions
Multiply. Write the answer in simplest form.
3
12
4
3
12
3


Write 12 as a fraction.
12
4
1
4
3
12 3
Simplify.


1 4
1
9
Multiply numerators. Multiply denominators.

9
1
7
Additional Example 1B Multiplying Fractions
Multiply. Write the answer in simplest form.
3
1

8
3
1

Simplify.
1
Multiply numerators. Multiply denominators.
1

8
8
Additional Example 1C Multiplying Fractions
Multiply. Write the answer in simplest form.
1
3


4
5
The signs are different, so the answer will be
negative.

Multiply numerators. Multiply denominators.
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Check It Out Example 1A
Multiply. Write the answer in simplest form.
1
16
4
1
16
1


Write 16 as a fraction.
16
4
1
4
4
16 1
Simplify.


1 4
1
4
Multiply numerators. Multiply denominators.

4

1
10
Check It Out Example 1B
Multiply. Write the answer in simplest form.
6
1

9
6
1

Simplify.
1
Multiply numerators. Multiply denominators.
1

9
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Check It Out Example 1C
Multiply. Write the answer in simplest form.
1
3


8
7
The signs are different, so the answer will be
negative.
Multiply numerators. Multiply denominators.
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Additional Example 2A Multiplying Mixed Numbers
Multiply. Write the answer in simplest form.
2
2

1
5
3
Write the mixed number as an improper fraction.
2
2
5
2

1


5
3
3
5
1
2
5


Simplify.
5
3
1
2
Multiply numerators. Multiply denominators.

3
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Additional Example 2B Multiplying Mixed Numbers
Multiply. Write the answer in simplest form.
1
1
4
2

7
5
1
1
21
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Write the mixed numbers as improper fractions.
4



2
5
7
7
5
3
3
15
21

Simplify.

5
7
1
1
Multiply numerators. Multiply denominators.
9
or 9

1
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Additional Example 2C Multiplying Mixed Numbers
Multiply. Write the answer in simplest form.
2
2
4
6

3
5
2
2
20
22
Write the mixed numbers as improper fractions.

4
6


3
5
3
5
4
20
22

Simplify.

3
5
1
Multiply numerators. Multiply denominators.
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Check It Out Example 2A
Multiply. Write the answer in simplest form.
3
1

2
5
3
Write the mixed number as an improper fraction.
1
3
7
3

2


5
3
3
5
1
3
7


Simplify.
5
3
1
7
2
Multiply numerators. Multiply denominators.
or 1
5
5
16
Check It Out Example 2B
Multiply. Write the answer in simplest form.
3
1
3
1

3
6
3
1
21
4
Write the mixed numbers as improper fractions.
3



1
6
3
3
6
7
2
4
21

Simplify.

6
3
1
3
Multiply numerators. Multiply denominators.
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Check It Out Example 2C
Multiply. Write the answer in simplest form.
1
1
1
3

6
3
1
1
19
4
Write the mixed numbers as improper fractions.

1
3


6
3
6
3
2
19
4

Simplify.

6
3
3
Multiply numerators. Multiply denominators.
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Additional Example 3 Transportation Application
In 2001, the car toll on the George Washington
Bridge was 6.00. In 1995 the toll was
2
of that
3
toll. What was the toll in 1995?






1
Simplify.
1
1
1
4.00
Divide 4 by 1 to write the fraction as a decimal.
The George Washington Bridge toll for a car was
4.00 in 1995.
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Check It Out Example 3
In 2002, the fee to park in a parking garage was
4. In 2000 the fee was of the fee in 2002.
What was the fee in 2000?
3
4
Simplify.
3.00
Divide 3 by 1 to write the fraction as a decimal.
The fee to park in the parking garage was 3.00
in 2000.
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Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
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Lesson Quiz Part I
Multiply. Write each answer in simplest form.
5
1
1.

8
6
5

2.
5
6
1
2
3.
5

1
10
3
3
2
7 8
4
4.

16
3
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Lesson Quiz Part II
Multiply. Write the answer in simplest form.
1
5.
A recipe for clam chowder calls for 2
pounds of
4
butter. If you prepare one-half of the recipe, how
much butter do you need?
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Lesson Quiz for Student Response Systems
1. Multiply. Write your answer in simplest
form. A. C. B. D.
1 9
4 5
4 45
1 9
1 6
1 10
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Lesson Quiz for Student Response Systems
2. Multiply. Write your answer in simplest
form. 4 A. or 5 C. or 1 B.
or 3 D.
4 5
1 3
3 5
17 3
8 5
2 3
16 5
4 5
1 5
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Lesson Quiz for Student Response Systems
3. Multiply. Write your answer in simplest
form. 6 1 A. or 8 C. or 5 B.
or 6 D. or 4
1 4
2 5
1 5
35 4
26 5
3 4
27 4
24 4
3 4
4 5
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Lesson Quiz for Student Response Systems
4. Multiply. Write your answer in simplest
form. 3 A. C. or 1 B.
D. 1
5 18
4 5
1 18
8 9
19 18
17 18
1 9
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Lesson Quiz for Student Response Systems
3 4
5. To prepare one bowl of salad, 3 pounds of
vegetables are required. How many pounds of
vegetables are required to prepare one-third bowl
of salad? A. 1 lb C. 1 lb B. 1 lb D.
1 lb
1 4
3 4
1 2
3 5