1.

Pythagorean theorem means that the sum of squares of right angles of right triangle is equal to the square of hypotenuse.

2. The difficulty of the circle.

The most important concept in a circle is pi, which refers to the ratio of the circumference to the diameter of a circle, and is approximately equal to 3.14159 (infinite acyclic decimal between 3 and 4).

3. The inside and outside angles of a triangle.

The sum of the inner angles of the triangle is 180, and the sum of the outer angles of the triangle is 360, which is rote knowledge. Not only a triangle, but also the sum of the external angles of any quadrilateral is equal to 360.

4. Solve the problem by segments.

Segmentation is an important problem-solving method in mathematics. Correct segmentation can play a vital role in solving problems.

1. Get ready.

In the unit preview, we can read roughly, understand the learning content in the recent stage, read carefully in the classroom preview, pay attention to the formation process of knowledge, and record the concepts, formulas and laws that are difficult to understand, so that we can listen to the class with questions. Persisting in preview, finding doubts and changing passive learning into active learning can greatly improve learning efficiency, and interest is the best teacher.

2. Listen carefully.

Listening to lectures should include listening, thinking and remembering. Listening: listen to the ins and outs of the formation of knowledge, listen to the key and difficult points, listen to the solutions and requirements of examples, listen to the mathematical thinking methods contained, and listen to the class summary. Thinking: First, be good at association, analogy and induction; Second, we should dare to question, ask questions and guess boldly.

3. Seriously solve the problem.

Classroom practice is the most timely and direct feedback. You must not miss them. Don't rush to finish your homework. Look at your notebook first. It is very important to review the learning content, deepen understanding and strengthen memory.

4. Correct mistakes in time.

Classroom exercises, homework, tests and feedback should be consulted in time to analyze the reasons for the wrong questions. Is there anything wrong with the exam? Is the concept blurred? Time is tight, no time? Won't you do it? Don't let yourself be careless (it will be very troublesome to form a habit), ask your classmates and teachers in time, don't leave the problem unresolved, and form a good habit of doing things today.