Transcript Positive and Negative Numbers

What You Will Learn
 Vocabulary related to integers.
 Situations in which we use integers
 Graph integers on a number line
 Find the absolute value of an integer
Are you ready??
Definition
Positive number – a number
greater than zero.
0 1 2 3 4 5 6
Definition
Negative number – a number
less than zero.
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
Definition
Opposite Numbers – numbers
that are the same distance from
zero in the opposite direction
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
Definition
Integers – Integers are all the
whole numbers and all of their
opposites on the negative
number line including zero.
7
opposite
-7
Definition
Absolute Value – The size of a
number with or without the
negative sign.
The absolute value of
9 or of –9 is 9.
What are integers used for?
Negative Numbers Are Used to
Measure Temperature
Negative Numbers Are Used to
Measure Under Sea Level
30
20
10
0
-10
-20
-30
-40
-50
Negative Numbers Are Used to
Show Debt
Let’s say your parents bought a car but
had to get a loan from the bank for $5,000.
When counting all their money they add
in -$5.000 to show they still owe the bank.
BRAINSTORM
NAME SOME SITUATIONS THAT
USE INTEGERS
Hint
If you don’t see a negative or
positive sign in front of a
number it is positive.
+9
Aren’t integers
interesting?
.
Name a positive or negative number to
represent each situation.
 A gain of 20 yards in the game against Union
 Spending $75 at Walmart
 Diving 10 feet below seal level
 An increase in allowance of $5
Which can not be represented by -8?
a) A temperature drop of 8
b) A depth of 8 meters
c) A growth of 8 centimeters
d) A time 8 years ago
Write about it!
Write a situation that each integer could represent.
a) 49
b) -83
c) -7
d) +15
Graphing Integers
 Graph -4 on a number line
 Graph 3 on a number line
Practice
 Graph the following on a number line:
 -5
2
Finding opposites
 Graph -6 on a number line.
 The opposite of -6 will be equal distance from zero on
the right side.
Finding opposites
 Graph 4 on a number line.
 The opposite of 4 will be equal distance from zero on
the left side.
Opposites Practice
 What is the opposite of the following?
-92
2. 75
3. -25
4. 9
1.
ABSOLUTE VALUE
 SYMBOL: | |
READING MATH
READ |3| AS THE ABSOLUTE VALUE OF 3
READ |-3| AS THE ABSOLUTE VALUE OF 3
 ABSOLUTE VALUE REFERS TO A NUMBERS
DISTANCE FROM ZERO
FINDING ABSOLUTE VALUE
 FACT I: ABSOLUTE VALUES ARE NEVER
NEGATIVE
 FACT II: OPPOSITE NUMBERS HAVE THE
SAME ABSOLUTE VALUE
FINDING ABSOLUTE VALUE
 USE A NUMBER LINE
 |5|
 |-7|
PRACTICE
 |418|
 |-189|
 |806|
 |-295|
Write about it!
 Why do opposites have the same absolute value?