Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
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Warm Up Simplify.
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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
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Learn to understand and select appropriate
customary units of measure.
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Vocabulary
customary system
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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 Customary Units of Length 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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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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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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Customary Units of Weight Customary Units of Weight 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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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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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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Capacity deals with volume, or the amount a
container can hold.
Customary Units of Capacity Customary Units of Capacity 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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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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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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Additional Example 4 Estimating
Measurements Estimate the length of the line
segment to the nearest half, fourth, or eighth of
an inch.
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Check It Out Example 4 Estimate the length of
the line segment to the nearest half, fourth, or
eighth of an inch.
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Lesson Quiz
What 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.
ft
in.
oz
gal
2 in.