# Arithmetic/Absolute Values

## Absolute value

The absolute value of a number is found by applying a simple rule: If you see a negative sign in front of the number, change it to a plus sign. If you see a plus sign, leave it alone. So, for example, the absolute value of -17 is +17. The absolute value of +36 is +36.

Another way to understand the absolute value of a number is to think about the number line:

The absolute value of a number is the distance from zero to that number on the number line.

The absolute value of x is usually written as |x|. On calculators and computers it is sometimes written as abs (x).

Questions: (note: if you don't see an answer box, do it on paper)
Calculate the absolute value of the following numbers:

1

 |-5|=

2

 |9|=

3

 |-3.8|=

4

 |-139,462|=

5

 |5/8|=

6 What is the absolute value of 0?

 |0|=

7 Why?

Calculate the following:

8

 |27|=

9

 |-1.9|=

10

 |3 - 7|=

11

 |3 - 0.5|=

12

 abs (-6)=

13 Draw a graph of abs(x) from -5 to +5.

14 Can abs(x) ever be less than zero?

 yes no

15 How can you see that from your graph?