The measurement of primary school mathematics angle is the fourth grade. The measurement of angle is the content of page 37~38 of unit 2 in the first volume of fourth grade primary school mathematics in the curriculum standard of People's Education Press. It is based on students' preliminary understanding of the types of angles, and further study the measurement of angles. This is the key content of this unit, and it is also the teaching difficulty.

Understand the protractor:

We can find the angle corresponding to the degree on the protractor, further understand the measurement unit of the angle and deepen the understanding of the diagonal meaning.

In the activities of independent exploration and communication with peers, understanding and mastering the methods of measuring and drawing angles with protractor can correctly measure and draw angles, understand the essence of measurement, accumulate experience in mathematical activities, and cultivate good study habits of careful operation in the process of drawing and measuring angles.