Class Notes
Complex Number System
Counting Numbers -
The numbers you count with starting with one.
Graph
-3
Whole Numbers -
-2
-1
0
1
2
3
The set of counting numbers including zero
Graph
-3
Integers -
-2
-1
0
1
2
3
Whole numbers and their opposites
(the opposite of zero is zero)
(Zero is neither positive nor negative it’s just zero)
Graph
-3
Rational Numbers -
-2
-1
1
2
3
Repeating and terminating decimals and fractions
1
$1.25
Irrational Numbers -
0
2
36
3
12
2
2
Non-repeating, non-terminating decimals and fractions
π
22
7
3.14
Uses of Integers
1.
Money
Ex.
Profit (+) or loss (-)
Checking/savings account: deposit (+) or withdraw (-)
What integer represents a withdrawal of $300?
What integer represents a profit of $15?
2.
Sports
Ex.
Football: yards gained (+) or yards lost (-)
Golf: above par (+) or below par (-)
What integer represents 3 under par?
What integer represents a gain of 7 yards?
3.
Temperature
Ex.
Degree above zero (+) or degrees below zero (-)
What integer represents 10° below 0°?
4.
Geographical
Ex.
Feet above sea level (+) or feet below sea level (-)
Miles north (+) or miles south (-)
What integer represents 2,000 meters below sea level?
What integer represents traveling 70 miles north?
5.
Time
Ex.
10 seconds to blast off (-10 because it’s before blast off)
10 seconds after blast off (+10)
What integer represents 5 seconds before the race starts?
6.
Number Line
What integer represents the number that is 3 units to the left of 0 on a
number line?
Absolute Value
The absolute value of an integer is its _______________ away from ____ on a number line.
The symbol for absolute value is
| |
(absolute value bars)
We ignore the sign of an integer that is inside the bars (+ or -), because absolute values are
____________ negative.
|x|
This means ---->
the absolute value of x
___________________________________________________________________
Use the number line above for the following examples.
1.
| 7 |=
4.
2.
|- 4|=
5.
| 0 |=
| 9 |=
6.
| |= 2
3.
-
-
|
-5
|=