This video tells you how to plot a real number on a number line. For example consider -3.1. You know -3.1 lies between -3 and -4. You also know -3.1 lies very close or next to 3. So all you have to do is, put a point just before -3. Now you have marked -3.1 on a number line. Similarly you can point any real number on a number line. It is quite an easy job to plot real numbers on a number line.