Transcript 7 X 8 + 2 X 9 - Effingham County Schools

Applying the IDENTITY,
COMMUTATIVE, and
ASSOCIATIVE properties of
multiplication.
Georgia Performance Standard:
I can apply the identity,
commutative, and associative
properties of multiplication and
verify the results.
IDENTITY Property of Multiplication
• When you multiply a number by 1, the
product is that number.
• EXAMPLES: 1 X 6 = 6
1X8=8
1 X 69 = 69
1 X 547 = 547
COMMUTATIVE Property of
Multiplication
• You can multiply two numbers in any
order. The product stays the same.
• EXAMPLE: 6 X 7 = 42
7 X 6 = 42
7X6=6X7
Commutative Property of
Multiplication
3 X 87 = 261
87 X 3 = 261
If 3 X 87 = 261, then 87 X 3 = 261
3 X 87 = 87 X 3
ASSOCIATIVE Property of
Multiplication
When you multiply three or more numbers, it
doesn’t matter which tow numbers you
group or multiply first. The product will stay
the same.
EXAMPLE: 2 X 4 X 3
(2 X 4) X 3
8X3
24
=
2X4X3
2 X (4 X 3)
2 X 12
24
ASSOCIATIVE Property
(6 X 7) X 3 = 6 X (7 X 3)
42 X 3
126
=
=
6 X 21
126
Solve using the identity,
commutative, or associative
property of multiplication.
7X1=?
What property of multiplication did
you use to help you solve the
problem?
Solve using the identity,
commutative, or associative
property of multiplication.
87 X 1 = ?
What property of multiplication
did you use to help you solve
the problem?
Solve using the identity,
commutative, or associative
property of multiplication.
1 X 258 = ?
What property of multiplication did
you use to help you solve the
problem?
Solve using the identity,
commutative, or associative
property of multiplication.
(3 X 4) X 6 = 3 X (4 X
)
What property of multiplication did
you use to help you solve the
problem?
Solve using the identity,
commutative, or associative
property of multiplication.
If 5 X 4 = 20, then 4 X 5 =
What property of multiplication did
you use to help you solve the
problem?
Solve using the identity,
commutative, or associative
property of multiplication.
(63 X 2) X 12 = 63 X (
X 12)
What property of multiplication did
you use to help you solve the
problem?
Model
What is the missing number?
21 X 9 =
A. 1
B. 9
C. 21
D. 189
X 21
Guided Group Practice
What is the missing number?
54 X 6 =
A. 324
B. 56
C. 6
D. 1
X 54
Guided Individual Practice
What is the missing number?
24 X 2 = 2 X
A. 48
B. 24
C. 2
D. 0
Independent Practice
What is the missing number?
36 X 5 = 5 X
A. 1
B. 5
C. 36
D. 180
Model
To multiply 7 X 4 X 5, you can multiply 4 X 5
first. What must you multiply by next?
A. 35
B. 28
C. 7
D. 4
Guided Group Practice
To multiply 6 X 2 X 10, you can multiply 2 X
10 first. What must you multiply by next?
A. 12
B. 10
C. 6
D. 2
Guided Individual Practice
To multiply 5 X 2 X 4, you can multiply 5 X 2
first. What must you multiply by next?
A. 2
B. 4
C. 5
D. 10
Independent Practice
To multiply 3 X 5 X 2, you can multiply 5 X 2
first. What must you multiply by next?
A. 2
B. 3
C. 5
D. 10
Model
Which number belongs in the
number sentence TRUE?
18 X
A. 0
B. 1
C. 18
D. 36
= 18
to make the
Guided Group Practice
Which number belongs in the
number sentence TRUE?
8X
= 24
A. 2
B. 3
C. 162
D. 282
to make the
Guided Individual Practice
Which number belongs in the
number sentence TRUE?
4X
= 36
A. 4
B. 8
C. 9
D. 144
to make the
Independent Practice
Which number belongs in the
number sentence TRUE?
7X
= 49
A. 7
B. 8
C. 9
D. 343
to make the
Model
If 8 X 16 = 128, then 16 X 8 =
A. 2
B. 16
C. 24
D. 128
Guided Group Practice
If 4 X 12 = 48, then 12 X 4 =
A. 48
B. 40
C. 4
D. 1
Guided Individual Practice
If 5 X 15 = 75, then 15 X 5 =
A. 5
B. 15
C. 55
D. 75
Independent Practice
If 2 X 55 = 110, then 55 X 2 =
A. 2
B. 55
C. 110
D. 120
Model
Which of the following does NOT have the
same product as 2 X 4 X 7?
A. (2 X 4) X 2
B. 2 X (4 X 7)
C. (2 X 4) X 7
D. 4 X 2 X 7
Guided Group Practice
Which of the following does NOT have the
same product as 4 X 8 X 9?
A. (4 X 8) X 9
B. 4 X (8 X 9)
C. (4 X 4) X 9
D. 4 X 8 X 9
Guided Individual Practice
Which of the following does NOT have the
same product as 2 X 5 X 9?
A. (2 X 5) X 9
B. 2 X (2 X 5)
C. (5 X 2) X 9
D. 9 X 5 X 2
Independent Practice
Which of the following does NOT have the
same product as 6 X 2 X 7?
A. (6 X 2) X 7
B. 6 X (2 X 7)
C. (6 X 7) X 2
D. 6 X 7 X 7
Model
What is the missing number?
5 X 95 = 95 X
A. 5
B. 90
C. 95
D. 475
Guided Group Practice
What is the missing number?
4 X 56 = 56 X
A. 224
B. 56
C. 4
D. 1
Guided Independent Practice
What is the missing number?
74 X 36 = 36 X
A. 1
B. 36
C. 74
D. 2,664
Individual Practice
What is the missing number?
4 X 92 = 92 X
A. 4
B. 92
C. 368
D. 2,956
Model
• Which is equivalent to the following?
8X5+5X7
a. 8 X 5 + 5 X 7
b. 8 X 7 + 5 X 5
c. 7 X 3 + 5 + 7
d. 8 + 5 X 5 + 7
Guided Group Practice
• Which is equivalent to the following?
14 X 6 + 8 X 12
a. 8 + 5 + 5 + 7
b. 14 X 12 + 6 X 8
c. 14 X 6 + 12 X 8
d. 14 + 6 X 8 + 12
Guided Individual Practice
• Which is equivalent to the following?
7X8+2X9
a. 7 + 8 + 2 + 9
b. 7 X 2 + 8 X 9
c. 7 X 8 + 2 + 9
d. 8 X 7 + 2 X 9
Independent Practice
• Which is equivalent to the following?
45 X 5 + 78 X 3
a. 45 X 3 + 78 X 5
b. 7 X 2 + 8 X 9
c. 7 X 8 + 2 + 9
d. 8 X 7 + 2 X 9
Lets review
How can I apply the identity, commutative,
and associative properties of multiplication
and verify the results.