Download 9.3 Multiply Multiples of 10 by 1

Name
9.3
?
Number and
Operations—3.4.G
Also 3.4.F, 3.5.D
MATHEMATICAL PROCESSES
3.1.C, 3.1.E, 3.1.F
Multiply Multiples of 10 by
1-Digit Numbers
Essential Question
How can you model and record multiplying multiples
of 10 by 1-digit whole numbers?
Hands
On
Unlock
Unlock the
the Problem
Problem
The community center offers 4 dance classes.
If 30 students sign up for each class, how many
students sign up for dance class altogether?
• How many equal
groups are there? _
• How many are
in each group? _
Activity Use base-ten blocks to model 4 × 30.
Materials ■ base-ten blocks
STEP 1 Model 4 groups of 30.
STEP 2 Combine the tens. Regroup
12 tens as 1 hundred 2 tens.
4 × 30 = _
So, _ students sign up for dance class altogether.
Math Idea
If one factor is a multiple
of 10, then the product
will also be a multiple
of 10.
Example Use place value and regrouping.
Find 7 × 40.
MODEL
STEP 1
THINK
Multiply the ones.
7 × 0 ones = _ ones
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STEP 2
Multiply the tens.
7 × 4 tens = 28 tens
RECORD
40
×
7
_
0
40
× 7
_
280
Regroup the _ tens
as _ hundreds _ tens.
So, 7 × 40 = _.
Module 9
287
Example Use Mental Math and the
Math Idea
Properties of Multiplication.
You can use mental math
to multiply multiples of 10.
You can change the order or the grouping
of the factors. The product is the same.
(20 × 3) × 2 = ■
20 × (3 × 2) = ■
20 × (3 × 2) = ■
Associative
Property
20 × (2 × 3) = ■
Commutative
Property
(20 × 2) × 3 = ■
20 × _ = _
Associative
Property
_×3=_
Share
Share and
and Show
Show
1.
Use the quick picture to find 5 × 40.
5 × 40 = _
Find the product.
2.
80
×_
9
3.
70
×_
7
4.
90
×_
4
5.
60
×
8
_
Use mental math or properties to group the factors another way.
Then find the product.
4 × (2 × 30)
7.
(50 × 2) × 2
8.
3 × (3 ×40)
____
____
____
____
____
____
Math Talk
Mathematical Processes
Explain how you can
use place value to solve
Exercise 5.
288
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6.
Name
Algebra Find the unknown factor.
9.
a × 80 = 480
a=_
10.
b × 30 = 30
11.
b=_
7 × ■ = 420
12.
■=_
50 × ▲ = 0
▲ =_
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Problem
Problem Solving
Solving
13.
Reasoning Multi-Step Ben writes the
product of 7 and 50. Then he subtracts the
least 3-digit multiple of 10 from the product.
What is the difference?
14.
Sense or Nonsense? Lori says
that 8 is not a factor of 80 because 8 does
not end in zero. Does Lori’s statement make
sense? Explain.
15.
Multi-Step Ava’s class
bought 6 packages of balloons for a school
celebration. Each package had 30 balloons.
If 17 balloons were left over, how many
balloons were used for the party?
16.
Analyze Frank has a 2-digit number on his
baseball uniform. The number is a multiple of
10 and has 3 as one of its factors. What three
numbers could Frank have on his uniform?
17.
Write Math
Show Your Work
Write Math
A landscaper planted 1 group
of 30 trees in 9 different city parks. How
many trees did he plant? Explain how you
grouped your factors to solve the problem.
Module 9 • Lesson 3
289
Mathematical Processes
M
Model ¥ Reason ¥ Communicate
M
Daily
Daily Assessment
Assessment Task
Task
Fill in the bubble for the correct answer choice.
18.
19.
20.
A food carnival visited Morris Elementary School.
During the show, 30 students each juggle 6 carrots.
How many carrots do the Morris Elementary School
students juggle?
A
180
B
36
C
60
D
6
Apply Asha bike jumps for 90 minutes every time she
practices. She practices 4 days each week. How many
minutes does Asha practice each week?
A
94
B
3,600
C
360
D
36
Multi-Step Vic makes ice pops in batches. He makes
2 batches of 20 cherry ice pops and 3 batches of 30 lime
ice pops. How many ice pops does Vic make?
A
90
C
50
B
40
D
130
21.
290
Wesley runs 10 miles each week for 2 weeks. Then he
runs 20 miles each week for 3 weeks. How many miles
does Wesley run in 5 weeks?
A
20 miles
C
60 miles
B
80 miles
D
30 miles
© Houghton Mifflin Harcourt Publishing Company
TEXAS Test Prep
Number and Operations—3.4.G
Also 3.4.F, 3.5.D
MATHEMATICAL PROCESSES 3.1.C, 3.1.E, 3.1.F
H o mewo rk
and Practice
9.3
Name
Multiply Multiples of 10 by 1-Digit Numbers
Find the product.
50
×
9
_
1.
2.
70
×
6
_
3.
90
× 7
_
4.
40
×
8
_
Use mental math or properties to group the factors
another way. Then find the product.
5.
3 × (3 × 20)
6.
4 × (2 × 50)
7.
(60 × 2) × 4
Problem
Problem Solving
Solving
8.
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10.
Rikki’s locker number is a two-digit
number. The number is less than
70 and is an even multiple of 10.
What three numbers could be Rikki’s
locker number?
9.
Jerry brings 8 packages of paper
plates to a picnic. Each package
contains 20 plates. If 23 plates were
left over, how many plates were used
at the picnic?
At the school play, there are 2 groups of seats. Each group of
seats has 5 rows that hold 30 people. How many people can be
seated at the play? Explain how you grouped your factors to
solve the problem.
Module 9 • Lesson 3
291
TEXAS Test Prep
Lesson
Lesson Check
Check
Fill in the bubble completely to show your answer.
13.
15.
292
Evelyn reads 40 pages of a book each
night for 5 nights. How many pages
does Evelyn read in all?
12.
Lamar walks for 40 minutes every
day. How many minutes does Lamar
walk in one week?
A
45
A
280 minutes
B
200
B
210 minutes
C
160
C
200 minutes
D
405
D
320 minutes
Mr. Carmello drives 30 miles each
way back and forth to work. If he
works 4 days each week, how many
miles does he drive in all?
14.
At the parade, there are 7 floats.
Each float has 30 people riding on it.
How many people ride on the floats
at the parade?
A
120 miles
A
308
B
304 miles
B
420
C
240 miles
C
210
D
210 miles
D
320
Multi-Step Luisa has 2 rows
of cabbage plants and 4 rows of
lettuce plants. There are 30 plants
in each row. How many plants does
Luisa have?
16.
Multi-Step A store has 3 crates
of sweet potatoes that each weigh
40 pounds. There are 4 crates of
white potatoes that each weigh
50 pounds. How many pounds of
potatoes are there?
A
200
A
280 pounds
B
180
B
360 pounds
C
120
C
420 pounds
D
240
D
320 pounds
© Houghton Mifflin Harcourt Publishing Company
11.