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Bellringer – Name the property (9 + 8) + 7 = 9 + (8 + 7) The Associative Property of Addition 12 + 0 = 12 The Identity Property of Addition 9 + 7 = 7 + 9 The Commutative Property of Addition

(9 + 8) + 7 = 9 + (8 + 7) The Associative Property of Addition 12 + 0 = 12 The Identity Property of Addition 9 + 7 = 7 + 9 The Commutative Property of

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Bellringer – Name the property

(9 + 8) + 7 = 9 + (8 + 7) The Associative Property of Addition

12 + 0 = 12 The Identity Property of

Addition9 + 7 = 7 + 9

The Commutative Property of Addition

Go Over Homework

Textbook page 10-11, problem 8-40

even show all your work

Skip Problem #34

Multiply DecimalsChapter 1, Section 3

Four Properties of MultiplicationFour Properties of Multiplication1. Commutative2. Associative3. Identity4. Zero Property

Communative Property of MultiplicationCommunative Property of Multiplication

Commuter A

Commuter B

Commuter A

Commuter B

A x B = B x A.

Remember… commute means to change.

The Commutative PropertyThe Commutative Property

A x B = B x AA x B = B x A

Commutative Property of

Multiplication

Changing the order of the factors does not change the product

A x B = B x A 1 x 2 x 3 = 3 x 1 x 2

4 x 5 x 6 = 5 x 6 x 4

Four Properties of MultiplicationFour Properties of Multiplication1. Commutative2. Associative3. Identity4. Zero Property

The Associative PropertyThe Associative Property

(A x B) x C = A x (B x C)

(A x B) x C = A x (B x C)

A C

B

A C

B

THEN THEN

The parentheses identify which two associates talked first.

Associative Property of

Multiplication

Changing the grouping of the factors does not change the product .

(1 x 2) x 3 = 1 x ( 2 x 3)

(4 x 5) x 6 = 4 x ( 5 x 6 )

(A x B) x C = A x ( B x C)

Four Properties of MultiplicationFour Properties of Multiplication1. Commutative2. Associative3. Identity4. Zero Property

Identity Property of MultiplicationIdentity Property of Multiplication

A x 1 = A

x 1 =

Identity Property of Multiplication

The product of one and anything is anything

1 x 3 = 3

18 x 1 = 18

1 x C = C

Four Properties of MultiplicationFour Properties of Multiplication1. Commutative2. Associative3. Identity4. Zero Property

Zero Property of MultiplicationZero Property of Multiplication

A x 0 = 0

x 0 = 0

Zero Property of Multiplication

The product of zero and anything is zero

3 x 0 = 0

18 x 0 =0

0 x C = 0

Let’s practice !Let’s practice !

Look at the problem.

Identify which property it represents.

(9 x 8) x 7 = 9 x (8 x 7)

The Associative Property

12 x 0 = 0

Zero Property

3 x1 = 3 The Identity Property

9 x 7 = 7 x 9

The Commutative Property

4 x1 = 4Identity Property

Numbers change places.

(4 x 3) x 2 = 4 x (3 x 2)

The Associative Property

It has parentheses!

a x b = b x aThe Commutative Property

Moving numbers!

a x 0 = 0 Zero Property

A

(a x b) x c = a x (b x c) The Associative Property

Parentheses!

C

B

1. Write the Problem

4 . 32x 0.012

*** Place values do NOT need to line up, but digits do!!!

Multiplying Decimals - Steps

2. Pretend decimals are not there!

4 . 32x 0.012

Multiplying Decimals - Steps

3. Multiply

4 . 32x 0.012 864+ 432000000

05184

Multiplying Decimals - Steps

4. Count total number of places behind ALL Decimals

4 . 32x 0.012 864+ 432000000

05184

2 places

3 places

5 total places!!

Multiplying Decimals - Steps

5. Place decimal that many places left.

. 05184

4 . 32x 0.012 864+ 432000000

05184

Multiplying Decimals - Steps

Textbook pg. 16 #1-10 & 20 together

3.41

Homework Time

Textbook page 16, problem 12-30 even show all your work

12- 18 do not estimate, give exact answer

30 show work (not extra credit)