In this section you'll learn how to find the absolute value using integers.

4 - 0 = 4

4 - 1 = 3

4 - 2 = 2

4 - 3 = 1

4 - 4 = 0

4 - 5 = -1

In this pattern you can see that 4 - 5 has a negative sum. A negative sum is something that is less than zero (in this case -1). A negative number is always less than zero, 0.

We can study this in a diagram. With example 0 - 4 = -4 and -1 - 3 = -4

This kind of diagram is called a number line. There are some things that you need to observe when you are drawing a number line. Zero, is always in the middle and separates negative and positive numbers. On the left side of zero you'll find numbers that are less than zero, the negative numbers. On the right side of zero you'll find numbers that are greater than zero, the positive numbers. The absolute value is the same as the distance from zero of a specific number.

On this number line you can see that 3 and -3 are on the opposite side of zero. This means that they are at the same distance from zero, in mathematics; they have the same absolute value - in this case 3.

Example:

Simplify the following expression

Video lesson: Evaluate the following expression

|x| + 11, x= -9

To see the solution look at the video in the next page.

We have an algebraic expression written as this: we have |x| (so these straight bars mean absolute va;ue) + 11. So this is just an algebraic expression, we want to evaluate this expression at x = -9. So we’re going to evaluate or plug in x = -9 right here. So if we do that we have |-9| + 11. So now the question is what do we do with this absolute value? Well absolute value means whatever the value is regardless of the sign in front of it so if it’s a plus or minus it’s just plus no matter what. So this -9 becomes 9. So how far away it is from 0. So 9 + 11 and of course 9 + 11 is 20. So this expression, evaluated at x = -9, is just 20.

why is it not showing that I am doing the modules?

-9 + 11 does not equal 20. So many errors in this course.

Am I reading the video wrong or is there a mistake? See below. [ 3 + (-3) = 3 ] equals [ 3 - 3 = 0 ] [ 3 + (-3) ] DOES NOT equal [ 3 + 3 = 6 ]

this makes no sense if the one number is negative it should be on the left of zero or negative..its totally counter intuitive..

excellent