Transcript Absolute Value - Gwinnett County Public Schools

Absolute Value
Just how far from zero are you?
What are opposites on a number
line?
Graph the integer set from –5 to + 5
Two numbers that are the same
distance from zero are said to be
opposites
But what is Absolute Value?
Absolute Value is the distance a
number is from zero. Remember
distance itself is ALWAYS positive
How do we denote absolute value?
x is the symbol used for absolute value. It is read the absolute value of
SO let’s try a few:
3 
5
0
What general statement can you
make about absolute value?
Be careful!
In math a negative sign in front of the
absolute value sign should be read
“take the opposite of”. This means
treat the absolute value sign like a
grouping symbol. Do the work inside
first THEN take the opposite of
Let’s try a few
 23 
65 4 
2
 
3
What if the variable is in the
absolute value sign?
x 7
This simply means what are ALL the solutions
that make this a true statement?
-7
0
7
Velocity and Speed
Velocity is how fast is something
going AND in what direction is it
headed? Example: If I am
plummeting to earth in a hot air
balloon my velocity would be –15
feet per second!
BUT my speed would be the
absolute value which is?
Final Thought for Today
In math it is not enough to just know the answer you
have to PROVE you know it. If you say something
is FALSE you must provide a counter example.
Give a counter example to this statement:
All of the students in Mrs. Rose’s algebra classes are boys.
Now determine if these are true or false. If false, provide a
counter example:
The expression – x is never positive
The absolute value of a number will always be greater than or
equal to that number
Individual Practice
Complete Section 2.2 in the practice workbook
Where are YOU now?
1: I have no clue what she is talking about!
5: I remember this from last year but better do my homework
and ask questions
10: This is a breeze. Bring on the homework!