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Name
LESSON
Date
Class
Practice B
3-2 Estimating Decimals
Estimate. Round to the indicated place value.
1. 7.462 ! 1.809; tenths
2. 15.3614 " 2.0573; hundredths
3. 56.4059 " 4.837; ones
4. 0.60871 ! 1.2103; hundredths
Estimate each product or quotient.
5. 42.1 # 5.97
6. 11.8 • 6.125
8. 7.539 • 3.0642
9. 80.794 # 8.61
7. 63.78 # 8.204
10. 19.801 • 2.78
Estimate a range for the sum.
11. 6.8 ! 4.3 ! 5.6
12. 12.63 ! 9.86 ! 20.30
13. Two sixth-grade classes are collecting money to buy a present
for one of their teachers. One class collected $24.68 and the
other class collected $30.25. About how much money did they
collect in all? The gift they want to buy costs $69.75. About how
much more money do they need?
14. On the highway, Anita drove an average speed of 60.2 miles per
hour. At that speed, about how far can she travel in three and a
half hours? At that same speed, about how many hours will it
take Anita to drive 400 miles?
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
21
Holt Middle School Math Course 1
Practice A
3-2 Estimating Decimals
Exploration Recording Sheet
3-2 Estimating Decimals
LESSON
LESSON
Round each decimal to the underlined place value.
For each problem, estimate a solution. Then compute with
a calculator to see how close your estimated solutions are
to the actual solutions.
1. 1.78
Estimate
1.
Seven people want to share the cost
of a $33.75 boat rental. How much
will each person pay?
$4.82
You purchase items that cost the
following amounts: $4.95, $1.29, $6.67,
$4.19, and $10.39. What is the total cost?
$27
$27.49
3.
How much change is there from
$200.00 for an item that costs $157.98?
$40
$42.02
4.
Ron’s gas tank holds 21 gallons and is
empty. If gas costs $1.499 per gallon,
how much will it cost to fill Ron’s tank?
20(1.5) ! $30
$31.48
2.
1.8
Actual
35
!! ! $5
7
2. 0.569
3. 12.62
0.57
4. 3.215
13
5. 24.608
3.2
6. 37.84
24.61
40
Estimate. Round to the indicated place value.
7. 3.67 " 1.23; tenths
8. 0.726 " 0.119; hundredths
4.9
0.85
9. 12.86 # 5.73; tenths
10. 8.643 # 2.795; nearest whole number
7.2
Think and Discuss
6
Estimate each product or quotient.
5. Discuss the estimation strategies you used.
11. 17.6 ÷ 6.2
Possible answer: 1 and 4: Use compatible numbers.
12. 1.9 • 7.045
3
2 and 3: Round to nearest dollar and nearest ten.
6. Describe a situation in which all you need is an
estimated solution and a situation in which you must
calculate an exact solution.
14
14. 9.02 • 4.65
6
15. 36.1 $ 3.9
45
Possible answer: Exact answer—grade point average;
13. 23.8 $ 4.3
16. 2.8 • 5.35
9
15
17. Tyler measured the growth of a plant for his science project.
When he started the project, the plant was 2.8 inches tall. At
the end of the project, the plant was 5.2 inches tall. About how
many inches did the plant grow during Tyler’s project?
estimated—number of people at a football game.
about 2 inches
18. Latoya bought 16.2 yards of cloth to make costumes for the
school play. She needs 3.8 yards of the cloth to make each
costume. About how many costumes can Latoya make with
the cloth she bought?
about 4 costumes
19
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 1
Practice B
3-2 Estimating Decimals
LESSON
Estimate. Round to the indicated place value.
1. 7.462 " 1.809; tenths
9.3
1. 102.68 " 57.209; ones
13.30
7
24
Estimate a range for the sum.
5. 24.674 • 5.578
8
60
from 15 to 17.5
9. 140.9 $ 11.756
280
from 41 to 43.5
400
Possible answers are given.
11. 8.4 " 3.1 " 9.54 " 2.86
12. 17.38 " 5.93 " 18.60 " 29.34
from 22 to 24
13. Two sixth-grade classes are collecting money to buy a present
for one of their teachers. One class collected $24.68 and the
other class collected $30.25. About how much money did they
collect in all? The gift they want to buy costs $69.75. About how
much more money do they need?
7
10. 48.6035 • 7.63
12
Estimate a range for the sum.
12. 12.63 " 9.86 " 20.30
7. 72.603 $ 10.164
10
8. 6.694 • 38.69
Possible answers are given.
11. 6.8 " 4.3 " 5.6
Possible answers are given.
6. 107.95 $ 9.193
150
10. 19.801 • 2.78
9
105.6
Estimate each product or quotient.
7. 63.78 $ 8.204
72
4. 99.97452 " 5.6409; tenths
206.1
Possible answers are given.
9. 80.794 $ 8.61
71.83
3. 215.673 # 9.5511; tenths
1.82
6. 11.8 • 6.125
2. 83.56912 # 11.7415; hundredths
160
4. 0.60871 " 1.2103; hundredths
51
8. 7.539 • 3.0642
Estimate. Round to the indicated place value.
2. 15.3614 # 2.0573; hundredths
3. 56.4059 # 4.837; ones
5. 42.1 $ 5.97
Holt Middle School Math Course 1
Practice C
3-2 Estimating Decimals
LESSON
Estimate each product or quotient.
20
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
from 69 to 72
13. For the first half of the year, the average monthly precipitation
levels in Atlanta, Georgia, are 4.8 inches, 4.8 inches, 5.8 inches,
4.3 inches, 4.3 inches, and 3.6 inches. Estimate the average
precipitation level in Atlanta for January through June. Then find
the actual average precipitation level for those months. How
does your estimate compare to the actual data?
about $55.00; about $15.00
about 5 inches; 4.6 inches; the estimate is close to the
14. On the highway, Anita drove an average speed of 60.2 miles per
hour. At that speed, about how far can she travel in three and a
half hours? At that same speed, about how many hours will it
take Anita to drive 400 miles?
actual data; it is an overestimate.
14. Tammy earns $14.68 per hour working as a chef. On average
she works 40.3 hours a week. About how much does Tammy
earn each week? About how much does she earn each year?
about 240 miles; about 7 hours
about $600 a week; about $31,200 a year
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
21
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 1
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
115
22
Holt Middle School Math Course 1
Holt Middle School Math Course 1