Third, it may be vague to say preview. You can discuss with your parents or classmates and find the correct answer in the cooperation and discussion of classmates. This will increase students' interest in exploring new courses, help them understand the practical use of mathematical knowledge and have an accurate concept of knowledge. You should also write "four writing, one writing and one writing" in preparation before class. During the preparation for the exam, you should take appropriate study notes, mainly including the initial experience and experience when reading a book, the understanding of the problems you have understood, and the recording and thinking of difficult problems. To do a preview application problem, you can draw a line segment to help you understand the relationship between quantity and quantity, find out the known conditions and problems, and find the way to solve the problem. For some graphics-related problems, you can do it in the preview, cut and spell it, and increase your perceptual knowledge. Six supplements and one supplement are often closely related to the old and new knowledge in mathematics class. If you find something unclear in the preview, you must understand it in the preview, consolidate your memory of old knowledge, and lay a solid foundation for learning new knowledge. Seven exercises are often typical examples of each class. When previewing, you should do all the examples to deepen your understanding. If you make mistakes in your exercises, you should think about where, why and how to correct them. If you still can't find the root of the error, you can listen carefully and understand slowly.