CCSS
Applyproblems
properties of
operations
as strategies toofmultiply
and
NS 2.4G3.OA.5
Solve simple
involving
multiplication
multi–digit
divide.2 Examples: If 6 x 4 = 24 is known, then 4 x 6 = 24 is also known. (Commutative
numbers by one-digit
numbers
then
___).
property of multiplication.)
3 x 5 x 2 can
be found(3,671
by 3 x 5= 315,
15 x 2 = 30, or by 5
x 2 = 10, then 3 x 10 = 30. (Associative property of multiplication.) Knowing that 8 x 5 =
40 and 8 x 2 = 16, one can find 8 x 7 as 8 x (5 + 2) = (8 x 5) + (8 x 2) = 40 + 16 = 56.
(Distributive property.)
CCSS G3.OA.7
UNDERLYING SKILLS AND CONCEPTS:
multiplication as repeated
addition
Fluently multiply and divide within 100, using strategies such as the
Distributive Property
a
K
ey Ide
The distributive property states that multiplying a sum by a
number is the same as multiplying each addend by the number
and then adding the products.
E x am p l E
1
Multiply 25 7.
Write 25 in expanded notation.
A model can help.
20 5
Think:
7 groups of 25.
25 20 5
Multiply each part by 7.
(20 7) (5 7)
35
175
E x am p l E
C – © CSL Associates, Inc. All rights reserved.
140
2
Multiply 42 8.
Write 42 in expanded notation.
42 40 2
Multiply each part by 8.
(40 8) (2 8)
320
page 126
+
16
= 336
Chapter 11 – Lesson 3
Name
P RAC T I C E
Use expanded notation to multiply.
1. 13 5
( 10 5) ( 3 5)
50
_____
+
15
_____
( 20 9) ( 1 9)
= _____
65
3. 36 6
+
36
_____
= _____
216
C – © CSL Associates, Inc. All rights reserved.
9
_____
= _____
189
280
_____
+
56
_____
= _____
336
6. 77 4
( 50 8) ( 2 8)
Math
Reasoning
+
( 40 7) ( 8 7)
5. 52 8
400
_____
180
_____
4. 48 7
( 30 6) ( 6 6)
180
_____
2. 21 9
+
16
_____
( 70 4) ( 7 4)
= _____
416
280
_____
+
28
_____
= _____
308
Number Sense
MR 3.2
7. Explain how to use expanded notation to multiply
a 2-digit number by a 1-digit number.
I first write the 2-digit number in expanded notation.
Then I multiply each of those numbers by the 1-digit
number and add the two products.
Chapter 11 – Lesson 3
page 127
MCX94.HW.CL.G3.FM&Lesson.v211
8/3/04
13:56
Page 86
Name
…at home!
P RAC T I C E
Use expanded notation to multiply.
1. 12 7
( 10 7) ( 20 7)
+
14
_____
= _____
84
3. 24 5
+
20
_____
= _____
120
5. 62 9
Math
Reasoning
+
7
_____
= _____
287
( 50 6) ( 80 6)
300
_____
+
48
_____
= _____
348
6. 63 4
( 60 9) ( 20 9)
540
_____
280
_____
4. 58 6
( 20 5) ( 40 5)
100
_____
( 40 7) ( 10 7)
+
18
_____
= _____
558
( 60 4) ( 30 4)
240
_____
+
12
_____
Number Sense
= _____
252
MR 3.2
7. Which shows how to use expanded notation to multiply
a 2-digit by a 1-digit number?
A.
B.
C.
D.
page 86
(8 10) (6 10) 20
(8 10) (6 10) 288
(80 10) (6 10) 860
(8 1) (6 1) 48
Home Resource and Homework
Chapter 11 Lesson 3
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70
_____
2. 41 7
MCX94TEG3Ch01_32.v8.9.3 2/21/01 14:46 Page 235
Name
P RAC T I C E
Use expanded notation to multiply.
1. 13 5
( 10 5) ( 3 5)
50
_____
+
15
_____
( 20 9) ( 1 9)
= _____
65
3. 36 6
+
36
_____
= _____
216
C – © CSL Associates, Inc. All rights reserved.
9
_____
= _____
189
280
_____
+
56
_____
= _____
336
6. 77 4
( 50 8) ( 2 8)
Math
Reasoning
+
( 40 7) ( 8 7)
5. 52 8
400
_____
180
_____
4. 48 7
( 30 6) ( 6 6)
180
_____
2. 21 9
+
16
_____
( 70 4) ( 7 4)
= _____
416
280
_____
+
28
_____
= _____
308
Number Sense
MR 3.2
7. Explain how to use expanded notation to multiply
a 2-digit number by a 1-digit number.
I first write the 2-digit number in expanded notation.
Then I multiply each of those numbers by the 1-digit
number and add the two products.
Chapter 11 – Lesson 3
Student Book Page
page 127
Name
…at home!
P RAC T I C E
Use expanded notation to multiply.
1. 12 7
( 10 7) ( 20 7)
+
14
_____
= _____
84
3. 24 5
+
20
_____
= _____
120
5. 62 9
Math
Reasoning
+
7
_____
= _____
287
( 50 6) ( 80 6)
300
_____
+
48
_____
= _____
348
6. 63 4
( 60 9) ( 20 9)
540
_____
280
_____
4. 58 6
( 20 5) ( 40 5)
100
_____
( 40 7) ( 10 7)
+
18
_____
= _____
558
( 60 4) ( 30 4)
240
_____
+
12
_____
Number Sense
= _____
252
MR 3.2
7. Which shows how to use expanded notation to multiply
a 2-digit by a 1-digit number?
A.
B.
C.
D.
page 86
(8 10) (6 10) 20
(8 10) (6 10) 288
(80 10) (6 10) 860
(8 1) (6 1) 48
Home Resource and Homework
Chapter 11 Lesson 3
C – © CSL Associates, Inc. All rights reserved.
70
_____
2. 41 7