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Name
LESSON
Date
Here
Class
Practice B
3-8 Dividing by Decimals
Find each quotient.
1. 9.0 ! 0.9
2. 29.6 ! 3.7
3. 10.81 ! 2.3
4. 10.5 ! 1.5
5. 15.36 ! 4.8
6. 9.75 ! 1.3
7. 20.4 ! 5.1
8. 37.5 ! 2.5
9. 9.24 ! 1.1
10. 16.56 ! 6.9
11. 28.9 ! 8.5
12. 14.35 ! 0.7
Evaluate the expression x ! 1.2 for the given value of x.
13. x " 40.8
14. x " 1.8
15. x " 10.8
16. x " 14.4
17. x " 4.32
18. x " 0.06
19. Anna is saving $6.35 a week to buy a
computer game that costs $57.15.
How many weeks will she have to
save to buy the game?
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
20. Ben ran a 19.5-mile race last
Saturday. His average speed during
the race was 7.8 miles per hour. How
long did it take Ben to finish the race?
76
Holt Middle School Math Course 1
Practice A
3-8 Dividing by Decimals
Exploration Recording Sheet
3-8 Dividing by Decimals
LESSON
LESSON
Find each quotient.
A CD store carries the packages of recordable CDs listed
in the table. Use a calculator to find the cost of 1 CD and
the purchasing power of $1.00 for each package.
Item
1. 2.4 ! 0.4
Cost
Cost of 1 CD
Purchasing Power
of $1.00
1 ! 1.19 " 0.84
6
Single CD
$1.19
1.19 ! 1 " 1.19
5-pack
$4.95
4.95 ! 5 " 0.99
5 ! 4.95 " 1.01
3.
4.
5.
10-pack
$8.95
20-pack
$16.95
50-pack
$35.95
8.95 ! 10 " 0.895
16.95 ! 20 " 0.8475
35.95 ! 50 " 0.719
10 ! 8.95 " 1.12
20 ! 16.95 " 1.18
50 ! 35.95 " 1.39
7. Which package gives you the lowest unit cost?
8
5. 1.8 ! 0.3
9
6. 6.4 ! 0.8
6
7. 3.3 ! 0.3
8
8. 2.6 ! 1.3
11
9. 7.2 ! 1.2
2
10. 7.5 ! 1.5
The third column above shows the cost of one CD for different
packages. This is called the unit cost. The fourth column shows
how many CDs one dollar can buy. For example, if you buy the
5-pack at $4.95, one dollar buys 1.01 CD (a little more than
one CD). This is called the purchasing power of $1.00.
3. 4.8 ! 0.6
7
4. 8.1 ! 0.9
1.
2.
6. Which package gives you the highest unit cost?
2. 1.4 ! 0.2
6
11. 6.0 ! 0.5
5
12. 9.9 ! 1.1
12
9
Evaluate 4.8 ! x for the given value of x.
Single CD
50-pack
13. x " 0.2
8. Which package gives you the greatest purchasing
power per dollar? the least purchasing power per dollar?
14. x " 0.4
24
50-pack; Single CD
12
16. x " 0.6
Think and Discuss
18. x " 1.2
6
19. Antonio spent $5.60 on cashews. They
cost $1.40 per pound. How many
pounds of cashews did Antonio buy?
Possible answer: The higher the unit cost the lower the
16
17. x " 0.8
8
9. Describe the relationship between unit cost and
purchasing power by looking at the numbers in the third
and fourth columns above.
15. x " 0.3
4
20. Over several months, a scientist
measured a total of 6.3 inches of
snow. The average snowfall each
month was 2.1 inches. How many
months did the scientist measure
the snow?
purchasing power.
4 pounds
74
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 1
Practice B
3-8 Dividing by Decimals
Find each quotient.
2. 29.6 ! 3.7
10
8
3.2
2.4
3.4
34
12
39.125
15. x " 2.5
9.78125
6.26
Evaluate.
17. (72 # 32.9) ! c for c " 3.5
16. n ! 7.8 for n " 26.988
0.05
3.46
2.5 hours
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
31.3
14. x " 1.6
19.5625
20. Ben ran a 19.5-mile race last
Saturday. His average speed during
the race was 7.8 miles per hour. How
long did it take Ben to finish the race?
76
6.047
12. x " 0.5
4.6
18. 18.67 # (0.216 ! x) for x " 0.02
19. 4.4t ! 1.6 for t " 16.92
7.87
46.53
20. The sum of two decimal numbers is
3.9. Their difference is 0.9, and their
product is 3.6. What are the two
numbers?
21. The sum of two decimal numbers is
5.3. Their difference is 1.7, and their
product is 6.3. What are the two
numbers?
2.4 and 1.5
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All rights reserved.
9. 0.489807 ! 0.081
11. x " 0.4
78.25
9
3.6
9 weeks
19.06
13. x " 0.8
18. x " 0.06
19. Anna is saving $6.35 a week to buy a
computer game that costs $57.15.
How many weeks will she have to
save to buy the game?
2.089
10. x " 0.2
20.5
1.5
17. x " 4.32
8.4
8. 97.206 ! 5.1
Evaluate 15.65 ! x for each value of x.
Evaluate the expression x ! 1.2 for the given value of x.
13. x " 40.8
14. x " 1.8
15. x " 10.8
16. x " 14.4
6. 0.1092 ! 0.013
25
7. 7.7293 ! 3.7
8.4
12. 14.35 ! 0.7
8
5. 168.75 ! 6.75
32.6
7.5
3. 10.0 ! 1.25
7.4
4. 283.62 ! 8.7
9. 9.24 ! 1.1
15
11. 28.9 ! 8.5
2. 34.04 ! 4.6
1.9
4.7
6. 9.75 ! 1.3
8. 37.5 ! 2.5
4
10. 16.56 ! 6.9
1. 4.75 ! 2.5
3. 10.81 ! 2.3
5. 15.36 ! 4.8
7
7. 20.4 ! 5.1
Holt Middle School Math Course 1
LESSON
Find each quotient.
4. 10.5 ! 1.5
75
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Practice C
3-8 Dividing by Decimals
LESSON
1. 9.0 ! 0.9
3 months
Holt Middle School Math Course 1
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
127
3.5 and 1.8
77
Holt Middle School Math Course 1
Holt Middle School Math Course 1