The basics are pretty simple. You have a line with small notches on it for numbers. If you are given a set of points, you can plot them one of two ways. Say you’re given a value that can be in between one and five. That could be expressed as such:
1Because your x value cannot include 1 or 5–it can be 2, 3 or 4 (including decimals)—you would use a closed dot, something that looks like this —> •
You would place this on the number line, on top of one and five.
However, if your given value can be anything from one to five including one and five, it would be expressed as such:
1 ≤x ≤5, or 1 is less than or equal to x, x is less than or equal to 5.
You would use an open dot, like this —> °
A number line can also include a mixture of the two.
For example, in the picture shown, the equation would be: -3 ≤x<1
x can be anything from -3 to 1, including -3 but not including 1.
These are just the basics.
