For junior two students, the expansion diagram of cube is the sublimation of spatial ability, and the expansion diagram of cube is a difficult point for students to learn because of its many styles. Therefore, teachers should try their best to help students straighten out some rules in a cube expansion diagram, so that students can remember and master it more conveniently and realize "a piece of cake" in actual judgment. However, if we simply let students realize their memory, it will change with our second curriculum reform. Contrary to students' experience, in order to combine students' memory and experience, hands-on operation and seeing is believing have become the main teaching methods of this course. First, know the basic concept of the cube expansion diagram: review the basic knowledge points of the cube before class, relearn the relevant knowledge that the cube has six faces, and gradually extend the knowledge of the cube expansion diagram composed of six small squares (six faces). Second, in the classification of cube expansion diagrams, I happily remembered 1 1 kinds of cube expansion diagrams: through observation, students found that some expansion diagrams have 4 pieces in the middle, some have 3 pieces, and so on. Then guide the students to observe the following two unfolded diagrams that can be folded into cubes (let the students cut them before class and try to fold them themselves) to find out the similarities and differences between the two unfolded diagrams. This causes students to question whether a new cube expansion diagram will be obtained if the next block is moved, which will be verified immediately. This process of putting forward assumptions and verifying them allows students to witness the process that some unfolded drawings can be folded into cubes. In this way, students have a firm memory and profound experience. Gradually, the students quickly summed up the first category, with four sides in the middle and one on each side, and there are six kinds of * * *.

In the same way, the students quickly found the development map of the two intermediate triplets around them. Through the method of rotation, the students found that its structure is somewhat similar to the expansion diagram of the middle triplet, except that a square on one side is moving, so it is easy to explore the third square expansion diagram of this type. So the children summed up another category: the second category, the middle triplet, one or two on each side, ***3 kinds. The rest is the students' favorite "staircase shape" (the third kind) (attached to the supporting cardboard). The students also confirmed the feasibility of folding these two kinds of unfolded drawings into cubes through previous folding. It is worth noting that the graphics that you often meet are often not exactly the same as the expansion diagram above, and their folding and rotating state also belongs to the expansion diagram of the cube. This kind of expansion diagram is often difficult to judge, so in class, I carefully designed a variety of flip and rotation expansion diagrams for students to judge, and further consolidated students' grasp of the three kinds of cubic expansion diagrams of 1 1 graphics in practice. Third, on the basis of correctly judging the cube expansion diagram, accurately identify three groups of "opposites": correctly identifying the cube expansion diagram is a test for senior two students, and correctly identifying the "opposites" is a challenge for them. This requires students to have a good spatial imagination, but not all children of this age have developed their spatial ability, so how can these students solve this problem? In class, my method is to let students mark "up, down, front, back, left and right" on the cube expansion diagram respectively. This method is simple, convenient and clear at a glance, and students can list three groups of faces quickly and accurately. For example:

Knowledge can be divided into difficulty and simple knowledge, which is easy for students to learn, but how to make students gain a sense of accomplishment in difficult knowledge acquisition? Therefore, the teacher's guidance is very important. Good guidance can make students think clearly, gain rich results and give good feedback. Students naturally like math, and interest is the best teacher to learn. Such a virtuous circle will inevitably have a good influence on students.