Integers & Life

Integers are used

to represent

many everyday situations

.

Weather

above zero

+

below zero

-

Business

earnings

+

debts -

Sea Level

above +

below -

Golf

above Par +

below Par -

Body Mass

gain +

loss -

Bank Account

Earnings

+

debts -

Stock Market

net gain +

net loss -

What is an integer?

We measure temperature in degrees Celsius. The highest temperature in Prince George, BC, on April 27, 2004 was 12oC. 12 is a positive number. 12oC is the difference between the temperature of the air and the temperature at which water freezes, 0oC. We may not be able to use a positive number to express a difference. For example, the temperature inside a freezer is 40C less than the freezing point of water. We represent this difference as -40C. -40C is a negative number. We say “negative 4.)”

A number with no fractional part. Includes the counting numbers {1,2,3,…}, zero {0}, and the negative of the counting numbers {-1, -2, -3, …}

You can write them down like this: {…, -3, -2, -1, 0, 1, 2, 3, …}

Use a positive or negative number to represent each situation.

~eight degrees above zero ~ten degrees below zero ~parking three levels below ground ~two points ahead in a game ~a loss of sixteen dollars ~taking four steps backward

Express each change as an integer regarding stock prices on the Toronto Stock Exchange:

The value of Apple Computers increased $2.00Palm Tech dropped from $25.00 to 22.00MDS started the day at $13.00 and ended the day at $12.00Steve bought Global stock at $10.00 and sold it for $15.00

Minds On:

How can an integer be used to show the relationship between two prices of a stock? Explain.

Minds On:The floors in the elevator at the Integer hotel are numbered from -3 to +7, with the street level lobby represented by L instead of zero. State which floor the elevator stops at after each of the following moves.

Hello my name is Jeeves,

welcome to my elevator. The person on my

left is not permitted to be at this hotel, please phone

security immediately!

Start Change Where are you0 up 4, down 3, down 4, up 3

0 floor

+2 down 5, up 10, down 2, down 1

+4 floor

-3 up 3, down 2, up 6, up 1, down 4

+1 floor

+6 down 7, up 3, up 5, down 9

-2 floor +5 up 2, down 5, down 3, up 1, up 7, down 8, up 5, up 3, down 7, down 1

-1 floor

Positive and negative whole numbers are called integers. We put a + in front of a number to indicate it is a positive integer. We put a – in front of a number to indicate it is a negative integer. We can show integers on a number line. The number line may be vertical, like a thermometer. A number line may be horizontal.

0+1+2+3+4

-1-2-3-4

Opposite integers are the same distance from 0 but are on the opposite sides of 0. For example, +2 and -2 are opposite integers. They are the same distance from 0 and are on the opposite sides of 0.

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