Constructivism teaching is not simply to let children "construct knowledge" without the guidance of teachers, but to reposition the position and value of teachers in teaching. Teachers are no longer the only protagonists in teaching activities and the authority leading children's learning, but have become the proposer and motivator of problems, the designer of teaching environment, the maintainer of teaching atmosphere, the helper of teaching process and the motivator of deep thinking. Teachers should have a more open and inclusive mind, more flexible communication methods and better teaching skills to help children actively construct their own knowledge concepts. Of course, teachers need to play different roles under different conditions and environments. Teachers should constantly switch between several roles according to the nature of conditions to meet children's learning needs.

First, the problem and motivation.

Teachers should contact their children's past learning experience and life experience to arouse their needs to solve problems, and then choose the content and scope suitable for their learning. Designing math problems with teachers and children can increase the spontaneity and challenge of children's problem solving.

Discussion on taking the bus

Teacher: If you leave home to visit the museum, and everyone has a 10 yuan fare, how are you going to get to the museum? (Children discuss in groups)

The first group:

Tao Tao: "Teacher, how much does it cost to go to the museum by taxi?"

(I estimated for them, starting from Peng Pu Xincun, probably going to 30 yuan. Immediately, some children think that they don't have enough money to take a taxi. )

Yao Yao: "Teacher, can I ask my mother to give me 20 yuan more?"

Teacher: "Our rule is per person 10 yuan."

Yao Yao: "Then I'll take two children to ride, and it costs 30 yuan for three people."

Tao Tao: "A taxi can take four people."

Yao Yao: "Then we can find four people to ride together and get more 10 yuan."

Teacher: "If it is shared by the four of you, how much will each of you pay?"

They calculated that everyone only needed 8 yuan money.

The second group:

Yuan Yuan: "We can take bus No.46 and go directly to the museum. And I like to take an air-conditioned car, as long as 2 yuan. "

Feng Feng: "There are too many people taking air-conditioned cars now. I think the ordinary bus is good, there are few people, and it only costs 1 yuan. "

The third group:

Yang Yang: "Take bus No.722 to the subway."

Han Han: "Let's walk to the subway station. It's cheaper."

Xinxin: "The subway in Peng Pu Xincun has not been opened to traffic. It's too far to walk to the subway station. "

Feifei: "I think we should take a taxi to the subway station first, and then transfer to the subway, so we don't have to beat around the bush."

Teacher: "Please think about it. Which method is the fastest? Which method is the cheapest? Which method is the most comfortable? Then choose the method you think is the best. "

The advantage of letting children participate in problem design is that children will integrate the experience problems in life into the problem situation. Secondly, children feel respected, especially these questions are not standard questions, which can give full play to their creativity in solving problems. In the discussion about taking the bus, the teacher's question triggered the children's discussion. They came up with various ways to allocate 10 yuan and chose various ways to reach their destination.