Number Lines:

We have seen that numbers on a number line can have "opposite" values, such as +3 and -3.
These numbers are the same distance from zero, but on opposite sides of zero.
Notice that the sum of these two opposite numbers is zero!
Such numbers are called "additive inverses" of each other.
-3 + 3 = 0
You can also arrive at an opposite number by multiplying by -1.
3 • (-1) = -3                   -3 • (-1) = 3

The opposite of the opposite of a number is the number itself.
-(-3) = 3

The value of 0 is its own opposite.

When working with absolute value, you must evaluate the absolute value before finding its opposite. For example: | -5 | = 5 whose opposite is -5.
So the opposite of | -5 | is -5. And the opposite of | 5 | is also -5.

Number Line Graphing:

Observations:
• As you move from left to right on a number line, the number values get larger.
7 > 4             4 > 0             0 > -4             -4 > -9

• Positive numbers are always larger than negative numbers.

• Zero is less than a positive number, but greater than a negative number.

Hint: When determining which of two negative numbers is larger (or smaller), picture them on the number line. The number to the right will be larger. The number to the left will be smaller.