Transcript Adding Integers

Complete the pyramid by filling in the missing
numbers. Each number is the sum of the
numbers in the two boxes below it.
-4
-8
–7
2
–9
4
–1
5
8
–3
You will need a pencil and a piece of paper. Title
your paper “Chapter 11 Mid-Chapter Check”
Page 173
1.
12
3.
-12
5.
-11
7.
2
9.
12
11. 14
13. 11
15. -11
17. 2
19. 16
21. -290
23.
-7 + 12 = 5
Page 174
1.
3 spaces
3.
-14
degrees
5.
-14 + 6 = -8 cm
7.
1 foot
Page 175
1. 3
3. -21
5. 7
7. 22
9. 10
11. 2
13. -12
15. 8
17.
19.
Deandre, 12;
Mazen, -9;
Esme, 16;
Shameeka, -2
-320 feet
Page 176
1.
3.
5.
$209,
$110,
-$40, -$52
$448
-29
degrees
Page 640
 #14-24, Even

You have 15 minutes.
 Make sure your name is on it.

How do I write
5+5+5
as multiplication?
How do I write
6+6+6+6+6
as multiplication?
How do I write
(-6)+(-6)+(-6)+
(-6)+(-6)?
as multiplication?


The number of students who bring their
lunch to Phoenix Middle School has been
decreasing at a rate of 4 students per month.
What integer represents the total change after
three months?
The integer -4 represents a decrease of 4
students each month. After 3 months, the
total change will be 3(-4).
You know that
multiplying two
positive integers
together gives you
a positive answer.
Look for a pattern
in the integer
multiplication at
right to
understand the
rules for
multiplying two
negative integers.
3(–200) = –600
2(–200) = –400
1(–200) = –200
0(–200) = 0
–1(–200) = 200
+ 200
+ 200
+ 200
The product of
–2(–200) = 400 two negative
integers is a
–3(–200) = 600
positive
integer.

Ways to express multiplication:
◦ x, parenthesis, ∙

+
For even numbers of factors:
◦ Same (like) signs = POSITIVE
◦ Different (unlike) signs = NEGATIVE
◦ Or draw a triangle…
Example: 3(4) =12
(-2)x(-7) = 14
(3)(-4) = -12
2(-7) = -14
-
-
Good Guys Leave town
+
-
Result
-
Good Guys
+
Stay in
town
+
Leave town
-
Result
+
Stay in
town
+
Result
-
Bad Guys
-
Bad Guys
-
Result
+
(8)2 = ?
 (-8)2 = ?
 Write the rule for powers of 2!

(2)3 = ?
 (-2)3 = ?
 Write the rule for powers of 3!


Try powers of 4 and 5. Is there a pattern?

Division can be written in two ways: ÷ or by a
fraction (top divided by the bottom number)

We call the answer to a division problem a
Quotient

For 2 factors:
◦ Like signs = POSITIVE
◦ Unlike signs = NEGATIVE

Try this:





(3)(-4)(4) ÷(-12) =
(24 ÷(-3))(7) ÷ 2 =
(-2)(-2)(4)(-2) ÷(-4)=
(7)(-2)(4) ÷(-14)(-2)=
#
#
#
#
of
of
of
of
negatives:
negatives:
negatives:
negatives:
2
1
4
3
If your problem has only multiplication or
division (no addition or subtraction signs) what
do you notice about even and odd number of
negatives?
(5)(-8)
Negative
(-3)(-4)(5)(-2)
Negative
(-12)(3)(-2)
Positive
(–12)(5) ÷ (-10)
Positive

http://www.teachertube.com/video/integers121930
Evaluate x-y if x=12 and y = -7
 Replace x and y with the numbers
above and solve:
x-y
12- (-7)
12+7
19

Evaluate 10 – x if x = (-8)
-2
Replace x with the number above and solve:

10 – (-8)
-2
18
-2
Notice that, in fraction form,
we do everything on top first.
The answer is -9
Evaluate ab ÷ c if a=5 and b= -12 and
c= -4.
 Replace a, b and c with the numbers
above and solve:

(5)(-12) ÷ (-4)
(-60) ÷ (-4)
15
Addition: Same sign: add and keep the sign
Different sign: subtract and keep the sign of
the number with the largest
absolute value
Subtraction: Change minus sign to a plus and flip the
sign of the 2nd number: Ex: 5-2 become 5+(-2) or 6(-2) becomes 6+2, then follow the addition rules.
____________________________________________________
Multiplication/Division: Like sign: Positive
Unlike sign: Negative
If it is all multiplication/division,
even negatives= positive
odd negatives = negative
 Pages
177-178, Odd
 Pages 181-182, Odd
 Due
at the start of next
class.