Name 1.5 Round Decimals

Name

1 . 5 Round Decimals

? Essential Question How can you use place value to round decimals to a given place?

Number and Operations--5.2.C

MATHEMATICAL PROCESSES 5.1.A, 5.1.E

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The Gold Frog of South America is one of the smallest frogs in the world. It is 0.386 of an inch long. What is this length rounded to the nearest hundredth of an inch?

One Way Use a place-value chart.

? Underline the length of the Gold Frog. ? Is the frog's length about the same

as the length or the width of a large paper clip?

? Write the number in a place-value chart and circle the digit in the place value to which you want to round.

? In the place-value chart, underline the digit to the right of the place to which you are rounding.

? If the digit to the right is less than 5, the digit in the place value to which you are rounding stays the same. If the digit to the right is 5 or greater, the digit in the rounding place increases by 1.

? Drop the digits after the place to which you are rounding.

So, to the nearest hundredth of an inch, a Gold Frog is

Ones Tenths Hundredths Thousandths

0?3

8

6

Think: Does the digit in the rounding place stay the same or increase by 1?

about __ of an inch long.

Another Way Use place value.

The Little Grass Frog is the smallest frog in North America. It is 0.437 of an inch long.

A What is the length of the frog to the nearest hundredth of an inch?

B What is the length of the frog to the nearest tenth of an inch?

0.437

0.44

7 > 5

0.437

0.4

3 < 5

So, to the nearest hundredth of an inch, the frog is

about __ of an inch long.

So, to the nearest tenth of an inch, the frog is about

__ of an inch long.

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Module 1 29

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Write the place value of the underlined digit. Round each number to the place of the underlined digit.

1. 0.673

___ ___

2. 4.282

___ ___

Name the place value to which each number was rounded.

4. 0.982 to 0.98

___

5. 3.695 to 4

___

3. 12.917

___ ___

6. 7.486 to 7.5

___

PPrroobblleemm SSoollvviinngg

Write the place value of the underlined digit. Round each number to the place of the underlined digit.

7. 0.592

___

8. 6.518

___

___

___

Round 16.748 to the place named.

10. tenths __

11. hundredths __

9. 0.809

___ ___

12. ones __

13. Write Math Explain why any number less than 12.5 and greater than or equal to 11.5 would round to 12 when rounded to the nearest whole number.

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14. Write Math nearest tenth.

Explain what happens when you round 4.999 to the

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Name

PPrroobblleemm SSoollvviinngg

Use the table for 15?18. 15. The speeds of two insects when rounded

to the nearest whole number are the same. Which two insects are they?

16. What is the speed of the housefly rounded to the nearest hundredth?

Insect Speeds (meters per second)

Insect

Speed

Dragonfly

6.974

Horsefly

3.934

Bumblebee

2.861

Honeybee

2.548

Housefly

1.967

17. The speed of an insect is about 3.9 meters per second. Which insect could it be?

Write Math Show Your Work

18.

What's the Error? Mark said

that the speed of a dragonfly rounded to the

nearest tenth was 6.9 meters per second. Is he

correct? If not, what is his error?

19.

Multi-Step A rounded number for the speed

of an insect is 5.67 meters per second. What are the fastest

and slowest speeds to the thousandths that could round to

5.67? Explain.

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Module 1 ? Lesson 5 31

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Fill in the bubble completely to show your answer.

20. Chef Round uses 1.257 kilograms of meat for his famous meatballs. There are four packages at the market. Which amount is closest to 1.257 kilograms? A 1.26 kg B 1.2 kg C 1.3 kg D 1.35 kg

21. Representations The table shows the neck lengths for four giraffes in the Long-Necked Friends Sanctuary. Which two giraffes have necks that are the same length when rounded to the nearest tenth?

A Spot and Stretch B Mittens and Spot C Mittens and Stretch D Spot and Zippy

Giraffe's Name Neck Length (feet)

Mittens

5.632

Spot

5.725

Stretch

5.405

Zippy

5.657

22. Multi-Step Janis sells friendship bracelets at a fair. She has three bracelets that are 16.53 cm, 16.755 cm, and 16.55 cm long. She wants to label the lengths to the nearest tenth of a centimeter. In order, how should she label the bracelets?

A 16.5 cm, 16.76 cm, 16.6 cm

B 16.6 cm, 16.7 cm, 16.5 cm

C 16.5 cm, 16.8 cm, 16.6 cm

D 16.3 cm, 16.5 cm, 16.5 cm

Mathematical Processes Model ? Reason ? Communicate

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TEXAS Test Prep

23. To which place value is the number rounded?

6.706 to 6.71

A ones

C hundredths

B tenths

D thousandths

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Homework and Practice

Name

1 . 5 Round Decimals

Write the place value of the underlined digit. Round each number to the place of the underlined digit.

1. 0.782

2. 4.071

Number and Operations--5.2.C MATHEMATICAL PROCESSES 5.1.A, 5.1.E

3. 21.939

4. 8.155

5. 34.09

6. 4.276

Round 8.293 to the place named.

7. hundredths _

8. tenths _

Round 12.462 to the place named.

10. tenths _

11. hundredths _

9. ones _ 12. ones _

PPrroobblleemm SSoollvviinngg

13. What is Anita's speed rounded to the nearest hundredth?

14. The speeds of two runners when rounded to the nearest tenth are the same. Which two runners are they?

Runner Speeds (meters per second)

Runner

Speed

Luke

0.178

Margola

0.169

Anita

0.277

Shateel

0.289

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Module 1 ? Lesson 5 33

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TEXAS Test Prep

Fill in the bubble completely to show your answer.

15. To which place value is the number rounded? 8.293 to 8.29

A ones B tenths C hundredths D thousandths

16. To which place value is the number rounded? 0.799 to 0.8

A ones B tenths C hundredths D thousandths

17. Which number is 5.389 rounded to the nearest hundredth? A 5.4 B 5.38 C 5.39 D 5.399

18. Which number is 7.323 rounded to the nearest tenth? A 7.3 B 7.4 C 7.32 D 7.33

19. A baker uses 2.327 kilograms of blueberries for muffins. There are four packages at the fruit market. Which amount is closest to 2.327 kilograms? A 2.3 kg B 2.42 kg C 2.33 kg D 2.4 kg

20. Multi-Step The chart shows the length of each student's pencil. Which person has a pencil length that can be rounded up to the nearest tenth of an inch?

A Lori

B Ping

C Jason

D Annie

Student Lori Ping Jason Annie

Pencil Length (inches) 6.61 5.055 4.91 6.5

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