1. Not affected by the arrangement of objects, explore the method of comparing the length of the route and correctly judge the length of the route. 2. Learn to observe and compare in operation activities, and correct mistakes in time when found. Preparation: digital seal, inkpad, record sheet, route model composed of four different colors and different numbers of jigsaw puzzles. Process: First, lead to the topic Teacher: Little brothers and sisters in small classes want to find the longest route for running competitions. But the road ahead of you is tortuous. Which route is the longest? They are in trouble. Children, can you help them find the longest route? Second, compare the route length 1. Show the route model and guide the children to observe. 2. Guide children to express their ideas and reasons for judgment, and give appropriate guidance to different answers. In the process of communication, teachers should give different guidance according to children's different reactions. For example, for those children who are quick-witted and have found the right method, the teacher can not make any evaluation for the time being, but encourage the children to verify their ideas through hands-on operation. Teachers should give appropriate guidance to those children who are reluctant and can't figure out a way at the moment. For example, through language inspiration: "Can the small hole in the toy help us?" Help them find a solution to the problem. Iii. children's operation activities 1. Explain the requirements. Teacher: Each group has four route models composed of different colors and different numbers of spliced toys. Please find the corresponding route model according to the line segment color on the record sheet, compare its length, and mark the judgment result in the position corresponding to the color on the record sheet. 2. Children's operation, the teacher's method of observing the length of children, and helping children with difficulties appropriately. Iv. activity evaluation 1. Show the children's record sheet and guide the children to observe. 2. Guide children to verify collectively. In the process of verification, teachers can not only guide children to compare the length of the route by counting the number of toys, but also guide children to compare the toys directly after they are put right, thus further verifying whether the comparison results are correct. 3. Promotion and summary. The teacher asked the child for advice in the voice of a younger brother and sister. On the one hand, it can echo from beginning to end, stimulate children's sense of responsibility and pride, on the other hand, it can help children sum up experience, review and sort out the process of activities. Reflection: Second, the principle of material selection In mathematics activities, the appropriateness of material selection often affects or even determines the success or failure of the whole teaching activity. Generally speaking, children gain relevant experience by operating activity materials. Therefore, if the activity materials provided by teachers can effectively expose some misunderstandings of children and help them finally get a correct understanding, then such materials can provide a strong guarantee for the effective development of teaching activities. So when designing this activity, I chose the most common mosaic toy in kindergarten, which is a cube, and each cube can be spliced and connected. The basic feature of this toy is that it can be combined into straight lines or curves. Children can compare the length of the route model assembled with this toy by counting the number of cubes. In addition, because this kind of toys can be inserted in any combination, children can also insert them into a straight line, and intuitively distinguish the length by direct comparison. Third, the design of the link design should focus on the teaching objectives, from shallow to deep, and gradually expand to guide children to move in the right direction. As far as this activity is concerned, teachers should first understand the general understanding of children, that is, how they judge the length of four different curve routes. Secondly, ask questions for children's misunderstanding, guide children to discuss and communicate, and determine the judgment criteria. Third, let the children verify their own judgments through operations, so as to gain a correct understanding and experience. Fourth, the guidance of the activity process When I showed the route model composed of toys that children are familiar with, the children's enthusiasm was effectively stimulated at once. Faced with four routes with different bending degrees, children have great differences and heated debates on judging which route is the longest. Faced with such a lively scene, I didn't rush to any conclusions, but guided the children to discuss and verify. By counting the number of toys, I found an effective way to compare the length of the route. In the communication session, I continue to guide the children to find the longest route by straightening and comparing. Through this process, the children finally formed the understanding that the length of the comparison route should be verified by practical methods such as counting and swinging, not just by eyes, so as to find the correct answer. (Southeast University Kindergarten Wu Lan)