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NS 2.5*1)
Compute
and perform simple multiplication and division of
PXOWLSO\DIUDFWLRQRUZKROHQXPEHUE\DIUDFWLRQ
fractions and apply these procedures to solving problems.
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GLYLVLRQWRGLYLGHIUDFWLRQVE\IUDFWLRQV
Multiply with Fractions
E x am p l E
1
Dorell’s mother brought home half a pizza.
Dorell got half of it.
How much pizza did Dorell get?
How much pizza did Dorell’s mother bring?
1
#
2
How much of this did Dorell get?
1
1
# of #.
2
2
Remember: “of” means multiply.
1
1
#?
So, what is #
!
2
2
Multiply the numerators together
and the denominators together:
1!1
1
1
1
# ! # " # " #.
2
!
2
2
2
4
1
Dorell got #
of a pizza.
4
page 196
So
!
and
1
1
of
2
2
understand the meaning of multiplying
fractions; use basic multiplication
facts;
find simplest form
Hey!
We have 12 pizza!
1
2
I
want
I
half
want
of it
half
too.
of it.
E x am p l E
2
In Mr. Adam’s class, half the students
are girls. Today, a quarter of the girls are
wearing skirts. What fraction of Mr. Adam’s
class is wearing skirts today?
Let’s rewrite the fractions words:
1
“half” means #
.
2
1
“a quarter” means #
.
4
So, the fraction of the class that wear skirts
1
1
1
1
#, or # ! #.
today is: #
of
2
4
2
4
Multiply the fractions:
1!1
1
1
1
# ! # " # " #.
2!4
2
4
8
1
So, #
8 of the class is wearing skirts.
"
" 1
4
Chapter 17 – Lesson 2
E – © CSL Associates, Inc. All rights reserved.
Here is a shortcut.
To multiply a fraction by
another fraction:
• Multiply the numerators.
• Multiply the denominators.
•Then simplify the product.
UNDERLYING SKILLS AND CONCEPTS:
Name
P RAC T I C E
Find the product of the two fractions. Simplify when possible.
1
1
1
2
2
1
1
1. 2.
2
3
4
3
6
12
6
1
1
1
1
1 4. 3
1
3
3
3
4
5. 4
7
5
2
7. 25
3
2
6
2
8. 5 9 45 15
10
1
10
12
3
28
7
5
3
3. 6
4
15
5
24
8
5
1
6. 8
3
5
24
9
7
63
23
9. 5 8 40 1 40
Rewrite the expression as a multiplication. Find the product. Simplify.
1
2
2
5
1
2
2
2
5
10
4
1
2
10. 11. 2 of 5 is:
3 of 2 is: 3 2 6 1 6 1 3
2
5
10
5
1
12. 4 of 9 is:
1
9
9
1
2
4
1
4
4
3
1
13. 8 of 8 is:
3
1
3
8
8
64
3
14. 7 of 5 is:
3
5
15
1
2
7
1
7
7
3
0
is:
15. of
4
2
3
0
0
0
4
2
8
E – © CSL Associates, Inc. All rights reserved.
Write an equation for each situation. Then solve.
16. The movie lasted one half hour. For a quarter of the movie,
Ben was so scared that he kept his hands over his eyes.
one-eighth
1
1
1
2
4
8
of an hour
17. Lee has an aquarium. Two-thirds of the fish are guppies and the rest
are sea horses. Five-sixths of the guppies are yellow.
2
5
10
5
of the fish
What fraction of her fish are yellow guppies?
3
6
18
9
How long did Ben keep his hands over his eyes?
Math
Reasoning
Fraction Products
MR 2.6
18. There are two fractions. When multiplied together, the product is 1.
What are the fractions? How do you make them?
1
2 2
3 4
5
and ; and ; and . To make
Many possible answers: 2
1 3
2 5
4
them, take any fraction, and reverse it to get the second one.
Chapter 17 – Lesson 2
page 197
MCX94.HW.CL.G5.FM&Lesson.v211
8/2/04
18:03
Page 132
Name
…at home!
P RAC T I C E
Find the product of the two fractions. Simplify when possible.
1
2
1
1
2
1
1
1. 2. 2
5
8
3
10
24
12
1
1
4. 4
1
1
4
2
5
7. 4
5
1
10
20
2
5
3
5. 5
7
15
3
35
7
2
4
1
8
8. 5
8
40
5
3
5
3. 12
4
15
5
48
16
1
5
6. 7
3
5
21
7 63
9
15
5
9. 1 1 6
8 48
48
16
Rewrite the expression as a multiplication. Find the product. Simplify.
2
7
1
2
1
2
2
2
7
14
2
1
1
10. of is:
11. of is: 2 2 2
7
3
2
2
7
14
7
3
2
6
6
3
1
12. of 8 is:
4
1
8
8
2
4
1
4
1
6
13. of is:
8
8
6
1
6
3
8
8
64
32
3
14. of 5 is:
5
15
3
5
3
5
1
5
0
3
15. of is:
7
2
3
0
0
0
14
2
28
16. The fireworks lasted forty minutes. For a quarter of the time,
10 minutes,
the sound was so loud that Isabel kept her hands over her ears.
or one-sixth
10
40
1
40
How long did Isabel keep her hands over her ears? of an hour
1
4
4
1
17. Miriam has chickens. Two-thirds of her chickens laid eggs today. The rest
did not. Five-eighths of her chickens that laid eggs are brown.
2
5
10
5 of her
What fraction of her egg-laying chickens are brown? 3
8
24
12 egg-laying
chickens
are brown.
Math
Reasoning
Fraction Products
MR 2.6
18. There are two fractions. When multiplied together, the product is 1.
What are the fractions? How do you make them?
1
2 2
3 4
5
and ; and ; and . To make
Many possible answers: 2
1 3
2 5
4
them, take any fraction and reverse it to get the second one.
page 132
Home Resource and Homework
Chapter 17 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
Write an equation for each situation. Then solve.
MCX94TEG5CH01_32.v7.4.2 2/24/01 19:47 Page 363
Name
P RAC T I C E
Find the product of the two fractions. Simplify when possible.
1
2
1
1
2
1
1
1. 2. 2
3
4
3
6
12
6
1
1
1
1
4. 1 3
1
3
3
2
5
7. 2
5
10
1
10
4
3
5. 4
7
12
3
28
7
2
3
2
6
8. 5
9
45
15
3
5
3. 6
4
15
5
24
8
1
5
6. 8
3
5
24
7
9
63
23
9. 1 5
8
40
40
Rewrite the expression as a multiplication. Find the product. Simplify.
2
5
1
2
1
2
2
2
5
10
4
1
2
10. of is:
11. of is: 1 1 2
5
3
2
2
5
10
5
3
2
6
6
3
1
12. of 9 is:
4
1
9
9
1
2
4
1
4
4
1
3
13. of is:
8
8
3
1
3
8
8
64
3
14. of 5 is:
7
1
3
5
15
2
7
1
7
7
0
3
15. of is:
4
2
3
0
0
0
4
2
8
E – © CSL Associates, Inc. All rights reserved.
Write an equation for each situation. Then solve.
16. The movie lasted one half hour. For a quarter of the movie,
Ben was so scared that he kept his hands over his eyes.
one-eighth
1
1
1
2
4
8
of an hour
17. Lee has an aquarium. Two-thirds of the fish are guppies and the rest
are sea horses. Five-sixths of the guppies are yellow.
2
5
10
5
of the fish
What fraction of her fish are yellow guppies?
3
6
18
9
How long did Ben keep his hands over his eyes?
Math
Reasoning
Fraction Products
MR 2.6
18. There are two fractions. When multiplied together, the product is 1.
What are the fractions? How do you make them?
1
2 2
3 4
5
and ; and ; and . To make
Many possible answers: 2
1 3
2 5
4
them, take any fraction, and reverse it to get the second one.
Chapter 17 – Lesson 2
Student Book Page
page 197
Name
…at home!
P RAC T I C E
Find the product of the two fractions. Simplify when possible.
1
1
1
2
2
1
1
1. 2.
2
5
8
3
10
24
12
1
1
4. 4
1
1
4
5
2
7. 45
10
1
20
2
3
5
5. 5
7
15
3
35
7
4
2
8
1
8. 5 8 40 5
5
3
3. 12
4
15
5
48
16
5
1
6. 7
3
5
21
9
7 63
15
5
9. 6 8 48 148 116
Rewrite the expression as a multiplication. Find the product. Simplify.
1
2
2
7
1
2
2
2
7
14
2
1
1
10. 11. 2 of 7 is:
3 of 2 is: 3 2 6 2 6 2 3
2
7
14
7
1
12. 4 of 8 is:
1
8
8
2
4
1
4
6
1
13. 8 of 8 is:
6
1
6
3
8
8
64
32
3
14. 5 of 5 is:
3
5
15
3
5
1
5
3
0
is:
15. of
7
2
3
0
0
0
14
2
28
16. The fireworks lasted forty minutes. For a quarter of the time,
10 minutes,
the sound was so loud that Isabel kept her hands over her ears.
or one-sixth
10
40
1
40
How long did Isabel keep her hands over her ears? of an hour
1
4
4
1
17. Miriam has chickens. Two-thirds of her chickens laid eggs today. The rest
did not. Five-eighths of her chickens that laid eggs are brown.
2
5
10
5 of her
What fraction of her egg-laying chickens are brown? 3
8
24
12 egg-laying
chickens
are brown.
Math
Reasoning
Fraction Products
MR 2.6
18. There are two fractions. When multiplied together, the product is 1.
What are the fractions? How do you make them?
1
2 2
3 4
5
and ; and ; and . To make
Many possible answers: 2
1 3
2 5
4
them, take any fraction and reverse it to get the second one.
page 132
Home Resource and Homework
Chapter 17 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
Write an equation for each situation. Then solve.