Lead-in before class is an indispensable part of complete classroom teaching. It is just like the "prelude" of movies and the "introduction" of music, which plays an important guiding role in the subsequent teaching work. Lead-in before class can help students concentrate and guide them into the learning state. At the same time, the pre-class lead-in also plays a role in paving the way for the new curriculum content. Mathematics is an important subject in primary school, and learning mathematics well is the goal of every student, because it is not only helpful for students' future study and further study, but more importantly, mathematics is a highly applied subject, which also occupies an important position in our daily life and work. As a primary school math teacher, if you want to do a good job in math teaching, you should pay full attention to every teaching link and try to do every detail well. Among them, paying attention to the lead-in skills before class is a problem that every math teacher should pay attention to. Compared with other stages of mathematics teaching, when teachers carry out mathematics teaching in primary schools, they must aim at a series of characteristics of primary school students of this age and use the skills of pre-class lead-in to maximize the potential of students and improve the teaching quality. So in our daily teaching work, what are the more commonly used methods of pre-class lead-in? First, the new introduction method of reviewing old knowledge is the most common introduction method before class, and it is also a method that many teachers like to adopt. Through this method, we not only reviewed the old knowledge, but also laid a good foundation for the teaching of new knowledge. Especially for the subject of mathematics, mathematics is a discipline with tight structure and strong logic, in which a lot of knowledge is interlocking, and problems in any link may affect students' mastery of new knowledge. For example, when learning the knowledge of "triangle classification", teachers can introduce new lessons by reviewing what they have learned before about "angle classification". First of all, the teacher can ask students to recall the angle classification they have learned before. At this time, many students began to think and replied that the angle classification they had learned before was "right angle, acute angle, obtuse angle, right angle and rounded corner", and then the teacher asked the students to explain what the basis of these angle classifications was. Under such layers of review and guidance, students gradually linked the "classification of angles" with the "classification of triangles", and then unconsciously entered a new lesson. Second, the introduction of physical demonstration method The characteristics of students' thinking mode in primary school are mainly manifested in image thinking, and some tangible things are the easiest for students to understand and accept. However, some mathematical knowledge is often abstract, which makes it difficult for primary school students who think in images to understand. At this time, if teachers can properly use some physical objects for teaching, it will be more conducive to students' understanding and digestion of knowledge. For example, when I talk about the content of "cubes and cubes", because cubes are slightly abstract knowledge, in order to make the knowledge as concrete as possible, I took out many physical objects of cuboids and cubes before class, let students observe these concrete physical objects, and then summarize the similarities and differences between cuboids and cubes according to the phenomena they observed. In this way, in the introductory stage, students have initially mastered the essence of this course, and then teachers will be very relaxed in the next teaching activities. Thirdly, introducing mathematics into life practice is a highly applied subject. In other words, mathematical knowledge can be seen everywhere in our real life. We can use this advantage of mathematics to introduce new courses from real life. For example, when teaching the knowledge of "percentage", I collected a lot of food packaging bags before class in order to let students personally understand the meaning of percentage. On these food packaging bags, there are descriptions of food ingredients, many of which are expressed in percentage. I ask students to carefully observe the information on these bags and then explain the meaning of percentage to students one by one. At this time, students will have physical objects as reference when understanding these percentages, which will be easier for students. At the same time, through real life as the starting point, students can also realize the important role of mathematics knowledge in our daily life, thus further stimulating students' interest in learning mathematics. Fourth, a very important psychological feature of primary school students is curiosity. Many students always instinctively want to know what they don't know, and curiosity is also recognized as an important internal driving force in psychology. In other words, if students have a strong curiosity about math problems, they will be inspired to study, think and explore, so that with a positive learning attitude, teachers will get twice the result with half the effort in teaching. Therefore, it is a good import method to carefully set doubts when using the pre-class import skills. For example, when I was talking about the knowledge of "equation", I first asked the students a question: "Four boxes of apples are 24 kilograms less than four boxes of pears, and each box of pears weighs 20 kilograms on average. How many kilograms does each basket of apples weigh? " As soon as many students saw this topic, they said they would do it, picked up a pen and began to calculate. After a while, some students worked out the correct answers. Then I asked, "Do you think this topic is difficult?" Many students said it was a bit difficult. At this time, I said to the students, "Today I will teach you a simple and quick way to do the problem. Once you learn this method, the speed of doing the problem will be twice as fast as now. " Hearing this, many students immediately opened their eyes and showed strong curiosity. In this way, when I begin to teach the knowledge of "equation", the students will show great interest. Five, the game is introduced to love to play is the child's nature. If teachers can make use of the attraction of games to children before class, it will be easy to stimulate students' interest in learning. For example, when I was teaching students how to use letters to represent numbers, I asked them to make one.