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Answer Key
Name
LESSON
4
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Date
Class
Practice B
4-1 Estimate with Decimals
Estimate by rounding.
1. 7.45 35.84
2. 64.08 23.47
3. 6.842 14.05
4. 7.156 8.34
5. 84.23 (78.24)
6. 3.78 2.078
7. 46.47 98.75
8. 357.24 56.38
9. 6.324 60.324
10. 28.318 18.955
11. 35.082 8.37
12. 62.49 12.84
Estimate using compatible numbers.
13. 59.69 19.904
14. 86.234 • 9.876
15. 54.87 • 19.47
16. 16.04 • 10.45
17. 31.25 • 6.57
18. 92.67 32.89
19. 5.548 • 12.38
20. 88.42 7.589
21. 90.05 6.21
22. Lisha works 20 hours per week at the bowling alley and makes
$8.55 an hour. She gets a raise of $1.30 an hour. Approximately
how much more will she make each week with her raise?
23. Miguel is able to save $87.34 each month. He wants to buy a
guitar that costs $542.45. For about how many months will
Miguel have to save before he can buy the guitar?
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
9
Holt Middle School Math Course 2
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CHAPTER
4
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Exploration Recording Sheet
4-1 Estimate with Decimals
Are You Ready? Recording Sheet
LESSON
Operations with Rational Numbers
For each problem, estimate a solution. Then compute with a
calculator to see how close your estimated solution is to the
actual solution.
Choose the best term from the list to complete each sentence.
decimal
fraction
improper fraction
decimal
1. A(n)
place value system.
fraction
3. A(n)
simplest form
is a number that is written using the base-ten
1. The lengths in kilometers of five paths of a bike trail are as follows:
21
8. 35
3
5
3
5
1
7
16. 38
64
5. 84
16
21
11
9. 99
1
9
15
2
13. 26
31
8
17. 89
66
6. 78
11
13
16
10. 36
4
9
1
3
64
7. 192
2
3
20
11. 30
23
20. 6
48
24. 5
3
95
5
4
17
6
14. 1
15
76
9
18. 47
14
29
15
29
7
1
35
11
2
15. 31
1
Estimate
Actual
28 km
28.69 km
b.
How long in miles is the bike
trail? (Hint: 1 mile 1.609 km.
Use 6.2 mi 10 km for your
estimate.)
28
4
6
17.83
miles
Sally traveled 7.7 kilometers
in 32 minutes. At this rate,
how long will it take her to
complete the whole bike trail?
4 30 120
119.23
minutes
9
59
10
39
23. 4
3
94
35
27. 8
48
19. 51
0
Think and Discuss
2. Discuss the estimation strategies you used.
Possible answer: Round to numbers easier to use; use closest
17
21. 3
2
53
whole number.
82
25. 9
99
1
29
22. 7
1
47
69
26. 4
174
1
3. Describe a situation in which all you need is an estimated solution
and a situation in which you must calculate an exact solution.
3
Possible answer: Number of gallons of paint needed to paint a room.
Exact answer for a grade point average.
Find each sum, difference, product, or quotient.
28. 11 (24)
35
32. 23 (30)
7
29. 11 7
30. 4 • (10)
18
31. 22 (11)
40
33. 33 74
2
34. 62 • (–34)
107
35. 84 (12)
7
2,108
3
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 2
Practice A
4-1 Estimate with Decimals
Estimate by rounding. Estimates
2. 1.91
2
11
5. 12.07
6
7. 8.4 15.9
24
10. 9.6 (7.2)
3
13. 16.8 4.3
13
8
19. 5.24 • 10.78
4. 7.156 8.34
19
15
7. 46.47 98.75
may vary.
8. 3.45 5.34
9. 9.36 7.542
8
53
17
11. 99.67 49.87
10. 28.318 18.955
12. 4.5 6.2
150
9
1
14. 34.25 18.5
13. 59.69 19.904
19
3
16. 16.04 • 10.45
answers given.
17. 6.35 • 1.83
12
18. 4.4 • 7.15
160
28
20. 29.1 • 5.15
19. 5.548 • 12.38
22. 16.2 3.5
4
150
45
23. 32.5 3.2
11
41
21
5. 84.23 (78.24)
6. 3.78 2.078
6
2
8. 357.24 56.38
9. 6.324 60.324
301
66
11. 35.082 8.37
12. 62.49 12.84
75
43
14. 86.234 • 9.876
answers given.
15. 54.87 • 19.47
860
1,100
17. 31.25 • 6.57
18. 92.67 32.89
210
3
20. 88.42 7.589
21. 90.05 6.21
11
15
22. Lisha works 20 hours per week at the bowling alley and makes
$8.55 an hour. She gets a raise of $1.30 an hour. Approximately
how much more will she make each week with her raise?
24. 36.34 2.1
$20
18
25. Cheri stopped for gasoline at a station that was
charging $1.89 per gallon. If Cheri had $12.45 in
cash, about how many gallons of gas could she buy?
3. 6.842 14.05
21. 14.25 • 2.99
72
55
may vary.
2. 64.08 23.47
Estimate using compatible numbers. Sample
15. 23.3 3.66
15
Estimate using compatible numbers. Sample
16. 7.9 • 0.6
43
6. 18.70
12
Estimate by rounding. Estimates
1. 7.45 35.84
3. 10.75
4
Holt Middle School Math Course 2
LESSON
Round to the nearest whole number.
4. 5.88
7
Copyright © by Holt, Rinehart and Winston.
Practice B
4-1 Estimate with Decimals
LESSON
1. 4.23
8.2
How long is the entire bike
trail?
c.
Write each improper fraction as a mixed number.
5
36
5.09
a.
Write each mixed number as an improper fraction.
12. 72
4.29
is a number that represents a part of a whole.
Write each fraction in simplest form.
24
4. 40
6.36
4.75
14
is 5 .
improper fraction
2. An example of a(n)
mixed number
23. Miguel is able to save $87.34 each month. He wants to buy a
guitar that costs $542.45. For about how many months will
Miguel have to save before he can buy the guitar?
about 6 gallons
about 6 months
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
8
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math
Course 2
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
128
9
Holt Middle School Math Course 2
Holt Middle School Math
Course 2