Multiplication and Division of Integers

1
Multiplication and Division of Integers
2
Cornell Notes
Notes
9/11/06
I will add integers
objective
Origin
The point on the line labeled zero
Summary or questions
3
Share out

• If your partner had an idea about multiplying or
  dividing with negative numbers, please share
  their thought.

Hey- your idea was great!
4
Heres a way I can Remember!

• To remember whether your answer will be positive
  or negative when MULTIPLYING or DIVIDING, well
  use

Mr. Multiplivision
5
When multiplying Integers, cover the Two signs
you are using
Choral Response
What sign is left uncovered?
Ex. 5 (-3)
Negative, - That is the sign of The answer
-15
6
Practice under time!
(raffle tickets)
(-10)(3)
21 ? -5
-13 ? -6
7
100
8
059
9
058
10
057
11
056
12
055
13
054
14
053
15
052
16
051
17
050
18
049
19
048
20
047
21
046
22
045
23
044
24
043
25
042
26
041
27
040
28
039
29
038
30
037
31
036
32
035
33
034
34
033
35
032
36
031
37
030
38
029
39
028
40
027
41
026
42
025
43
024
44
023
45
022
46
021
47
020
48
019
49
018
50
017
51
016
52
015
53
014
54
013
55
012
56
011
57
010
58
009
59
008
60
007
61
006
62
005
63
004
64
003
65
002
66
001
67
000
68
Division
Its not any different!
Good News
Ex. -48 ? (-4)
12
69
Reminder

• Equal means it works both ways!

?
70
Boss and Secretary
Person B Boss first
Partner A Secretary first
Tell the secretary what to write in solving
Copy exactly what boss says

• SOLVE
• (4)(-7) ? (-2)

Then switch!
71
Grade your boss work

• (4)(-7) ? (-2)
• First, (4)(-7)
• - 28
• Finish it! (-28)?(-2)

Answer 14
72
4
(-56 ? 7) ? - 2
210
5 ? -7 ? -6
- 135
73
Why does it all work?
74
Properties of Multiplication

• Identity a ? 1 a and 1 ? a a
• Zero Property a ? 0 0 and 0 ? a 0
• Property of -1 a(-1) -a and (-1)a -a

75
Distributive Property
How will we use this with integer multiplication?

• a (bc) ab bc
• -1 (5 7) (-1)5 (-1)7

Also,
-7
(-1) 7
76
Heres How to Use It

• Ex. (-7) 6
• (-1) (7 ?6) - 42

77

• (-1)(-1) ?

1
Why??
78
Vocabulary

• Reciprocal
• Two numbers whose product is 1.
• Ex. reciprocal of a

79
More on Reciprocal

• Ex.

-2