Use the simplest language to determine the mathematical theme to be drawn.

Let's take the measurement of angle as an example. An angle is a figure composed of two rays drawn from a point. So let's learn about rays first. Draw line segments and straight lines with rays and compare their similarities and differences. Let's first mark the key words on the mind map about the important knowledge points of angle.

In this mind map, we know that the definition of light comes from angle, and we can draw the relationship line between angle and light, which is convenient for us to connect knowledge points in series.