Download Algebra • Break Apart Ones to Subtract Lesson 5.1

Lesson 5.1
Name
Algebra • Break Apart Ones
to Subtract
Essential Question How does breaking apart
a number make subtracting easier?
Number and Operations
in Base Ten—2.NBT.B.5
MATHEMATICAL PRACTICES
MP1, MP5, MP6
Listen
Listen and
and Draw
Draw
© Houghton Mifflin Harcourt Publishing Company
Write two addends for each sum.
7
9
5
6
4
8
Math
Talk
FOR THE TEACHER • After children have
recorded addends for each sum, have a class
discussion about the different facts that children
represented on their papers.
Chapter 5
MATHEMATICAL PRACTICES 6
Describe how you
chose addends for
each sum.
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317
Model
Model and
and Draw
Draw
Break apart ones. Subtract in two steps.
Start at 63.
Subtract 3 to get
to 60. Then subtract
4 more.
63 − 7 = ■
3
4
-4
-3
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
So,
63 − 7 = —.
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Break apart ones to subtract. Write the difference.
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
55 − 8 = —
5
2.
3
42 − 5 = —
2
3
3.
41 − 9 = —
4.
53 − 6 = —
5.
44 − 7 = —
6.
52 − 8 = —
318
three hundred eighteen
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1.
Name
On
On Your
Your Own
Own
Break apart ones to subtract. Write the difference.
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
7.
75 − 7 = —
8.
86 − 8 = —
9.
82 − 5 = —
10.
83 − 7 = —
11.
72 − 7 = —
12.
76 − 9 = —
13.
85 − 8 = —
14.
71 − 6 = —
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15.
16.
SMARTER
Cheryl brought
27 bagels for the bake sale.
Mike brought 24 bagels.
They sold all but 9 of
them. How many bagels
did they sell?
MATHEMATICAL
PRACTICE
— bagels
1
Analyze Lexi
has 8 fewer crayons than
Ken. Ken has 45 crayons.
How many crayons does
Lexi have?
Chapter 5 • Lesson 1
— crayons
three hundred nineteen
319
MATHEMATICAL PRACTICES COMMUNICAK<›G<IJ<M<I<›CFEJKIL:K8I>LD<EKJ
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Write or draw to explain.
17. Cheryl built a toy train with
27 train cars. Then she added
18 more train cars. How many
train cars are on the toy
train now?
— train cars
18.
MATHEMATICAL
PRACTICE
1
Analyze
Samuel had 46 marbles. He gave
some marbles to a friend and has
9 marbles left. How many marbles
did Samuel give to his friend?
19.
— marbles
SMARTER
Matthew had 73 blocks.
He gave 8 blocks to his sister. How
many blocks does Matthew have now?
Matthew has — blocks now.
TAKE HOME ACTIVITY • Ask your child to describe
how to find 34 − 6.
320
three hundred twenty
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Draw or write to show how to solve the problem.
Practice and Homework
Name
Lesson 5.1
Algebra • Break Apar t Ones to
Subtract
COMMON CORE STANDARD—2.NBT.B.5
Use place value understanding and properties of
operations to add and subtract.
Break apart ones to subtract.
Write the difference.
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
1.
36 − 7 =
3.
37 − 9 =
5.
44 − 5 =
7.
32 − 4 =
—
—
—
—
2.
35 − 8 =
4.
41 − 6 =
6.
33 − 7 =
8.
31 − 6 =
—
—
—
—
Problem
Problem Solving
Solving
Choose a way to solve. Write or draw to explain.
9. Beth had 44 marbles. She gave
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9 marbles to her brother.
How many marbles does
Beth have now?
— marbles
10.
Math
Draw a number line and
show how to find the difference for
24 – 6 using the break apart method
in this lesson.
Chapter 5
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321
Lesson Check
(2.NBT.B.5)
1. What is the difference?
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
58 − 9 =
(2.OA.B.2, 2.NBT.B.6)
2. What is the difference?
14 − 6 =
—
4. What is the sum?
64 + 7 =
322
—
3. What is the sum?
3 + 6 +2 =
—
5. What is the sum?
56 + 18 =
—
FOR MORE PRACTICE
GO TO THE
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Personal Math Trainer
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Spiral Review
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