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9-1Understanding CustomaryUnits of Measure9-1 Understanding Customary

Units of Measure

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Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Course 1

9-1Understanding CustomaryUnits of Measure

Warm UpSimplify.

28

1.

48

3.

616

2.

1216

4.

14

38

12

34

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9-1Understanding CustomaryUnits of Measure

Problem of the Day

Maria rented an electric car at a rate of $40 per day and $0.15 per mile. She returned the car the same day, gave the rental clerk a $100 bill, and got $21.75 back in change. How far did Maria drive the car?255 miles

Course 1

9-1Understanding CustomaryUnits of Measure

Learn to understand and select appropriate customary units of measure.

Course 1

9-1Understanding CustomaryUnits of Measure

Vocabulary

customary system

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9-1Understanding CustomaryUnits of Measure

If you do not have an instrument, such as a ruler, scale, or measuring cup, you can estimate the length, weight, and capacity of an object by using a benchmark. The customary system is the measurement system often used in the United States. It includes units of measurement for length, weight, and capacity.

Customary Units of Length

Unit Abbreviation Benchmark

Inch in. Width of your thumb

Foot ft Distance from your elbow to your wrist

Yard yd Width of a classroom door

mile mi Total length of 18 football fields

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9-1Understanding CustomaryUnits of Measure

Additional Example 1: Choosing Appropriate Units of Length

What unit of measure provides the best estimate? Justify your answer.

A. A doorway is about 7 _____ high.

B. A calculator is about 6 _____ long.

Think: The height of a doorway is about 7 times the distance from your elbow to your wrist.A doorway is about 7 ft high.

Think: The length of a calculator is about 6 times the width of your thumb.

A calculator is about 6 in. long.

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9-1Understanding CustomaryUnits of Measure

Check It Out: Example 1

What unit of measure provides the best estimate? Justify your answer.

A. A 4-door sedan is about 5 _____ long.

B. A students desk is about 3 _____ long.

Think: The length of a sedan is about 5 times the width of a classroom door.

A 4-door sedan is about 8 yd long.

Think: The length of a students desk is about 3 times the distance from your elbow to your wrist.

A students desk is about 4 ft long.

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9-1Understanding CustomaryUnits of Measure

Customary Units of Weight

Unit Abbreviation Benchmark

Ounce oz A slice of bread

Pound lb A loaf of bread

Ton T A small car

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9-1Understanding CustomaryUnits of Measure

Additional Example 2: Choosing Appropriate Units of Weight

What unit of measure provides the best estimate? Justify your answer.

A. A loaf of bread weighs about 16 _____ .

B. A bike could weigh 20 _____ .

Think: A loaf of bread has a weight of about 16 slices of bread.A loaf of bread weighs about 16 oz.

Think: A bike could have a weight of about 20 loaves of bread.

A bike could weigh 20 lbs.

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9-1Understanding CustomaryUnits of Measure

Check It Out: Example 2

What unit of measure provides the best estimate? Justify your answer.

A. A black rhino could weigh about 1 _____ .

B. A DVD remote control weighs about 8 ____ .

Think: A black rhino has a weight of about a small car.A black rhino can weigh about 1 T.

Think: A DVD remote control has a weight of about 8 slices of bread .

A DVD remote control weighs about 8 oz.

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9-1Understanding CustomaryUnits of Measure

Capacity deals with volume, or the amount a container can hold.

Customary Units of Capacity

Unit Abbreviation Benchmark

Fluid ounce fl oz A spoonful

Cup c A glass of juice

Pint pt A small bottle of salad dressing

Quart qt A small container of paint

Gallon gal A large container of milk

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9-1Understanding CustomaryUnits of Measure

Additional Example 3: Choosing Appropriate Units of Capacity

What unit of measure provides the best estimate? Justify your answer.

A large water cooler holds about 10 _____ t of water.

Think: A large water cooler holds 10 times the amount of a large container of milk.

A large water cooler holds about 10 gal of water.

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9-1Understanding CustomaryUnits of Measure

Check It Out: Example 3

What unit of measure provides the best estimate? Justify your answer.

A small fish aquarium holds about 20 _____ t of water.

Think: A small fish aquarium holds 20 times the amount of a small container of paint.

A small fish aquarium holds about 20 qt of water.

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9-1Understanding CustomaryUnits of Measure

Additional Example 4: Estimating Measurements

Estimate the length of the line segment to the nearest half, fourth, or eighth of an inch.

1 2

The line segment is closest to 1 in. 5 8

The length of the line segment is about 1 in.5 8

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9-1Understanding CustomaryUnits of Measure

Check It Out: Example 4

Estimate the length of the line segment to the nearest half, fourth, or eighth of an inch.

1 2

The line segment is between 1 and 1 in. 1 4

3 8

The length of the line segment is closest to 1 in.1 4

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9-1Understanding CustomaryUnits of Measure

Lesson QuizWhat unit of measure provides the best estimate?

1. A row boat is 10 _____ long.

2. A skateboard is 30 _____ long.

3. A pair or earphones weighs 4 _____.

4. Drinking water is delivered in 5 _____ bottle.

5. Estimate the length of the line segment to the

nearest half, fourth, or eighth of an inch.

in.

ft

oz

gal

2 in.

1 2