Applications of Negative Numbers & Absolute Value

Applications of Negative Numbers

&Absolute Value

In

Algebra County

Zero

Down here, temperatures are negative.

Negative Numbers are found in

weather reports, but not in sunny

Florida!

There, the stock market went down.

Negative Numbers are found in stock market quotes

When losing

weight, the weight loss

is a negativenumber.

The number of feet below

sea level is a

negative number.

The number of feet below

sea level is a

negative number.

The number of feet below

sea level is a

negative number.

The number of feet below

sea level is a

negative number.

Checks are “subtracted” fromthe bank statement.

Negative Numbers are found

in banking.

Negative Numbers are found

in Jeopardy scores.

INALGEBRA COUNTY

ADDING INTEGERS

If it’s 70 degrees outside, and the temperature gets 10 degrees cooler, how can we write it?

70 10 60

If it’s -10 degrees outside, and the temperature goes down 10 degrees, how can we write it?

10 10 20

A positive added to a negative takes the sign of the largest “number.” We subtract.

If it’s 5 degrees outside, and the temperature gets 10 degrees colder, how can we write it?

5 10 5

A negative added to a negative is a “larger” negative. We add the “numbers.”

Another way to think of adding positive and negative numbers is by using red and yellow colored counters.

3 53 and -5 2

zero pairs

3 5 -3 and -5 8

No zero pairs

1. 18 20 22. 11 9 23. 6 5 114. 1 7 85. 2 9 76. 7 5 2

Write these in your notes pages

INALGEBRA COUNTY

MULTIPLYING INTEGERS

-5 TIMES 6CAN BE WRITTEN:

-5(6) -5 ·6(-5)(6)

2(3) MEANS:

•2 GROUPS OF 3

•A 2 BY 3 ARRAY

WE CAN PICTURE 2(3):

THESE AREALL ARRAYS

WE CAN PICTURE 2(3) AS 2 GROUPS OF 3:

Which?Group or array?

3 keys on

two key rings

A six-pack of cokesTwo rows of three

kitchen tiles

Two stacks of three books

The chairs

in church

When we multiply:

Positive X positive =Positive X negative =

Negative X positive =Negative X negative =

+-

-+

Don’t get confused:

Positive + positive =Positive + negative =

Negative + positive =Negative + negative =

+??

??-

Negative + positive =??

Why the question marks?

-4+6=2 (positive)

-6+4= -2 (negative)

Back to multiplication:

-(-3) means: - (-3)1

= 3Negative 1 times negative 3The number 1 is very

important in Algebra County.

Also: -(5) means:- (5) which

is:-5Negative 1 times

51

Let’s work some multiplication problems:

-2(5) -10=

3(-5) -15=

-4(-2) 8=

- (-6) 6=

-9(-11) 99=

- (-13) 13=