These are the signs that are usually used for inequalities.
We are using the signs as a way to form a line on the graph, or a way to know where to shade in.
Here is an example of how those signs are used.
Well first what you do is you graph the inequality y > x + 1, and since the sign is greater than you shade above the line , then the next equation which is y > -x you graph that one and since that one also is greater than you shade above than you see where the two meet.