Name
3.2
?
Number and
Operations—5.3.D
MATHEMATICAL PROCESSES
5.1.D, 5.1.E
Multiply Decimals and
Whole Numbers
Essential Question
How can you use a model to multiply a whole number
and a decimal?
Hands
On
Investigate
Investigate
Materials ■ decimal models ■ color pencils
Giant tortoises move very slowly. They can travel a distance
of about 0.17 mile in 1 hour. If a giant tortoise travels at the same
speed, how far could it move in 4 hours?
A. Complete the statement to describe the problem.
I need to find how many total miles are in _ groups
of __.
• Write an expression to represent the problem. __
B. Use the decimal model to find the answer.
• What does each small square in the decimal model represent?
____
C. Shade a group of _ squares to represent the
distance a giant tortoise can move in 1 hour.
D. Use a different color to shade each additional
© Houghton Mifflin Harcourt Publishing Company
group of _ squares until you
Math Talk
Mathematical Processes
Explain how the model
helps you determine
if your answer
is reasonable.
have _ groups of _ squares.
E. Record the total number of squares shaded. _ squares
So, the giant tortoise can move __ mile in 4 hours.
Module 3
111
Hands
On
Make
Make Connections
Connections
You can use base-ten blocks to solve decimal multiplication
problems. A quick picture is a way to record your work.
Find the product. 3 × 0.46
STEP 1
Make 3 groups of 4 tenths and 6 hundredths. Remember that a square
or a flat is equal to 1. Draw a quick picture to record your work.
STEP 2 Combine the hundredths and rename.
There are _ hundredths. I will rename _
hundredths as __. In your quick picture, cross out
the hundredths you renamed.
STEP 3 Combine the tenths and rename.
There are _ tenths. I will rename _ tenths as
__. In your quick picture, cross out the tenths you
renamed.
STEP 4 Record the value shown by your completed quick picture.
Math Talk
So, 3 × 0.46 = __.
Mathematical Processes
Explain how renaming
decimals is like renaming
whole numbers.
Share
Share and
and Show
Show
Use the decimal model to find the product.
4. 3 × 0.62 = __
112
2. 2 × 0.38 = __
3. 4 × 0.24 = __
5. 4 × 0.32 = __
© Houghton Mifflin Harcourt Publishing Company
1. 5 × 0.06 = __
Name
Problem
Problem Solving
Solving
Use the table for 6–8. Use quick pictures or
base-ten blocks to help.
6. Each day a bobcat drinks about 3 times as much
water as a Canada goose drinks. How much water
does a bobcat drink in one day?
7.
Multi-Step River otters drink
about 5 times as much water as a bald eagle
drinks in a day. How much water does a river
otter drink in three days?
© Houghton Mifflin Harcourt Publishing Company • Image Credits: (tr) ©Photodisc/Getty Images
8.
9.
Water Consumption
Animal
Average Amount
(liters per day)
Canada Goose
0.24
Cat
0.15
Mink
0.10
Opossum
0.30
Bald Eagle
0.16
Write Math
Explain how you could use a quick
picture to find the amount of water that a cat drinks in 5 days.
Write Math
Show Your Work
Compare the product of 0.46 and 3 with each of
the factors. Which number has the greatest value? Explain how
this is different than multiplying two whole numbers.
Module 3 • Lesson 2
113
Mathematical Processes
M
Model ¥ Reason ¥ Communicate
M
Daily
Daily Assessment
Assessment Task
Task
Fill in the bubble completely to show your answer.
10. Representations What multiplication expression does the model show?
A
5 × 0.4
C
16 × 0.05
B
5 × 0.6
D
5 × 0.16
11. Display Which equation matches the model?
A
4 × 0.31 = 1.24
C
4 × 0.39 = 1.24
B
4 × 0.31 = 1.51
D
4 × 0.39 = 1.56
12. Multi-Step Use Diagrams Use a quick picture to multiply 3 × 0.16.
Then multiply the result by 3 again. What is the final product?
A
0.32
C
1.44
B
0.48
D
1.24
TEXAS Test Prep
that weighs 3 times as much as Jared’s parakeet. How many ounces does
Susie’s parrot weigh?
114
A
0.32 ounce
C
4.32 ounces
B
43.2 ounces
D
0.43 ounce
© Houghton Mifflin Harcourt Publishing Company
13. Jared has a parakeet that weighs 1.44 ounces. Susie has a Senegal parrot
Number and Operations—5.3.D
MATHEMATICAL PROCESSES 5.1.D, 5.1.E
H o mewo rk
and Practice
3.2
Name
Multiply Decimals and Whole Numbers
Use the decimal model to find the product.
1. 4 × 0.07 = __
2. 3 × 0.21 = __
3. 4 × 0.13 = __
Find the product. Draw a quick picture.
4. 3 × 0.38 = __
5. 2 × 0.41 = __
© Houghton Mifflin Harcourt Publishing Company
Problem
Problem Solving
Solving
6. Lars walks his dog 4 times farther than Michelle
7. One day, Nat’s dog drank 3 times as much water
walks her dog. Michelle walks her dog 0.23 mile.
How far does Lars walk his dog?
as his cat. If his cat drank 0.83 liter of water, how
many liters did his dog drink?
Module 3 • Lesson 2 115
TEXAS Test Prep
Lesson
Lesson Check
Check
Fill in the bubble completely to show your answer.
8. Which equation matches the model?
9. Sidney’s bag of popcorn weighs 1.89 ounces.
Sam’s bag of popcorn weighs 4 times as much
as Sidney’s. What is the weight of Sam’s bag
of popcorn?
0.756 ounce
B
7.56 ounces
A
5 × 0.18 = 0.9
C
75.6 ounces
B
5 × 0.18 = 90
D
756 ounces
C
5 × 0.18 = 9.0
D
5 × 0.18 = 0.09
11. In a swimming race, Yvonne swam 0.18 mile.
fills another beaker with 3 times as much
water. How much water is in Leon’s beaker?
David swam 4 times as far as Yvonne. How far
did David swim?
A
0.96 liter
A
2.2 miles
B
0.84 liter
B
0.22 mile
C
0.69 liter
C
7.2 miles
D
0.47 liter
D
0.72 mile
12. Multi-Step Carrie has 0.73 liters of juice
in her pitcher. Sanji’s pitcher has 2 times as
much juice as Carrie’s pitcher. Lee’s pitcher
has 4 times as much juice as Carrie’s pitcher.
Sanji and Lee pour all their juice into a large
bowl. How much juice is in the bowl?
A
1.46 liters
B
4.38 liters
C
2.92 liters
D
5.11 liters
13. Multi-Step Justin and Hayden are playing a
number game. Justin’s number is the product
of 4 × 0.06. Hayden’s number 0.04 less than
the product of Justin’s number and 4. What is
Hayden’s number?
A
0.92
B
0.96
C
0.60
D
1.0
© Houghton Mifflin Harcourt Publishing Company
10. A beaker is filled with 0.23 liter of water. Leon
116
A