Multiplication of Real Numbers

1
Multiplication of Real Numbers
2
Practice Multiplication

• http//www.rockwood.k12.mo.us/Marquette/bowdern/Al
  gebra20I/Power20Points/Multiplying20Real20Numb
  ers.pdf

3
Multiplication Properties

• Commutative Property
• Associative Property
• Identity Property
• Zero Property
• Distributive Property
• Property of -1

4
Why Should you Learn about the Properties of
Multiplication?

• It helps you solve problems without working them
  out.
• It helps with mental math.
• It makes understanding math easier.

5
Commutative Property

• The order of the numbers doesnt change the
  result (answer to the problem)
• p X q q X p

6
Commutative Property

• 9 X 3 3 X w
• 56 X p 11 X 56
• q X 8 8 X 4
• 5 X 9 r X 5
• The answers are on the next slide.

7
Commutative Property

• 9 X 3 3 X 9
• 56 X 11 11 X 56
• 4 X 8 8 X 4
• 5 X 9 9 X 5

8
Associative Property

• The grouping of the factors doesnt change the
  answer.
• (p X q) X r p X (q X r)

9
Associative Property

• 3 X (4 X 2) (n X 4) X 2
• 4 X (p X 7) (4 X 1) X 7
• 5 X (7 X 2) (5 X 7) X n
• (2 X z) X 5 2 X (8 X 5)
• Is this Associative?
• 5 X (n X 2) (2 X 5) X 5 Watch out!
• Answers are on the next slide.

10
Associative Property

• 3 X (4 X 2) (3 X 4) X 2
• 4 X (1 X 7) (4 X 1) X 7
• 5 X (7 X 2) (5 X 7) X 2
• (2 X 8) X 5 2 X (8 X 5)
• Is this Associative? No, its commutative.
• 5 X (5 X 2) (2 X 5) X 5

11
Identity Property

• Any number multiplied by 1 will give you the
  original number.
• 23,487 X 1 23,487

12
Identity Property

• 234 X 1 z
• q X 2,567 2,567
• 98,765 X d 98,765
• Answers are on the next slide.

13
Identity Property

• 234 X 1 234
• 1 X 2,567 2,567
• 98,765 X 1 98,765

14
Zero Property

• When any number is multiplied with zero, the
  answer is zero.
• 98,756,432 X 0 0

15
Zero Property

• 7,547,598,375 X c 0
• 758,375,937 X 0 b
• z X 75,879,705 0

16
Property of -1

• Any number multiplied by -1 is its opposite
• Ex. 5.6546 x -1
• Ex. -9.7 x -1

17
Test Yourself
Rewrite each equation with the correct answer,
and write the name of the property.

• 9 X 3 3 X w
• 3 X (4 X 2 ) (n X 4) X 2
• 234 X 1 z
• 56 X p 11 X 56
• 7,547,598,375 X c 0
• q X 8 8 X 4
• 5 X (7 X 2) (5 X 7) X n
• 4 X 509 (4 X 500) (4 X m)
• 6 X 310 (6 X n) (6 X 10)

• (2 X z) X 5 2 X (8 X 5)
• q X 2,567 2,567
• 12. 195 X 5 (200 X 5) (5 X t)
• z X 75,879,705 0
• 98,765 X d 98,765
• 5 X 9 r X 5
• s X 205 (5 X 200) (5 X 5)
• 4 X (p X 7) (4 X 1) X 7
• 758,375,937 X 0 b

18
Test Yourself Answers

• 9 X 3 3 X 9 Commutative
• 3 X (4 X 2) (3 X 4) X 2 Associative
• 234 X 1 234 Identity
• 56 X 11 11 X 56 Commutative
• 7,547,598,375 X 0 0 Zero
• 4 X 8 8 X 4 Commutative
• 5 X (7 X 2) (5 X 7) X 2 Associative
• 4 X 509 (4 X 500) (4 X 9) Distributive
• 6 X 310 (6 X 300) (6 X 10) Distributive

• (2 X 8) X 5 2 X (8 X 5) Associative
• 1 X 2,567 2,567 Identity
• 195 X 5 (200 X 5) (5 X 5) Distributive
• 0 X 75,879,705 0 Zero
• 98,765 X 1 98,765 Identity
• 5 X 9 9 X 5 Commutative
• 5 X 205 (5 X 200) (5 X 5) Distributive
• 4 X (1 X 7) (4 X 1) X 7 Associative
• 758,375,937 X 0 0 Zero

19
How did you do?

• 18 correct Excellent
• 17 correct Very Good
• 16 - 15 correct Good
• 14 - 13 correct Passing
• 12 0 correct You need more practice.

20
Classwork/Homework

• Pg 91 1-47 odd