The overall task is the overall grasp of a unit. Therefore, teachers can take corresponding measures to correct and remedy in time, and give students targeted re-explanation and guidance, so as to achieve twice the result with half the effort and enable students to master and apply what they have learned skillfully.

1, determine the teaching objectives and grasp the teaching content.

Setting the goal of unit teaching is actually setting the direction for unit teaching. Whether we can correctly deny the direction depends on whether we can correctly handle the relationship between the whole and the part, knowledge and ability according to the characteristics of mathematics, so as to make the set goals scientific, accurate and measurable.

Once the goal has the above three characteristics, it can really become the starting point and reference system for teachers to organize teaching activities, judge teaching effects and standardize teaching process. In this way, the goal of preparing lessons will make teaching less detours because of the clear direction.

2. Grasp the key points and teach students the methods.

First of all, find out the relationship between the knowledge involved in this unit in terms of old and new, difficulty and mutual restriction, and find out the knowledge that plays a key role. Secondly, on the basis of carefully studying which old knowledge is closely related to this key knowledge, spend 3 ~ 5 minutes reviewing the old knowledge.

Once it is confirmed that students have the cognitive premise of learning new knowledge, it is necessary to put the teaching of key and difficult knowledge in the central position, organize various forms of teaching activities with teaching methods suitable for children's intellectual activities, and even let most students fully understand and master these knowledge.

Obviously, grasping the key points mainly includes two meanings: one is to study the knowledge structure of the textbook, find out the teaching of key and difficult knowledge that can affect the whole unit teaching, and let students effectively master the method of learning this unit.

3. Grasp self-study and let the students answer by themselves.

Self-study is the study of students under the guidance of teachers. Because in the second step of unit teaching, students have mastered the method of learning the unit. After entering the third step, the main task of teachers becomes to go deep into students' self-study in a planned and purposeful way, and carefully observe how students use the mastered methods to solve mathematical problems. Find out the problems existing in the process of students' answering questions in time, and provide timely and appropriate counseling according to the feedback.