When a teacher called "two digits plus one digit (carry)", he changed the presentation mode of "explanation" (stick) in the textbook to "problem discovery", allowing students to explore independently. This teacher designed it like this: "Dad asked Mingming to calculate 18+7, and Mingming thought hard for a while and asked his classmates for help. Who has a clever way to help me? "

A stone stirs up a thousand waves, and the students are in high spirits and think positively. At this moment, teachers organize students to discuss in time, give full play to the collective role and embody the spirit of unity and cooperation through group discussion and deskmate talk, so that every student has the opportunity to take the initiative to participate and strengthen multi-directional communication between students.

The teaching strategies to solve the problems are designed as follows:

1, create situations and collect information

When teachers start classes, they can create vivid and interesting teaching situations with the help of theme maps or teaching courseware, and connect abstract mathematics knowledge with real life. The information in the theme map or teaching courseware provides clues for students' thinking in a certain sense.

After the students report, the teacher instructs the students to sort out the collected information and find out the problems that need to be solved. Observation and report can also provide a cognitive basis for solving problems, stimulate students' desire for knowledge, glow students' subjective consciousness, and create an atmosphere for students to explore and solve problems independently.

2, group cooperation, explore the problem

When students are clear about the problems to be solved, they should leave enough space and time for students, so that each student can use the existing knowledge and experience to independently find ways, methods and strategies to solve the problems, or they can discuss and communicate with each other in groups to form a preliminary plan. In this process, teachers should participate in the group to obtain information in time, and conduct appropriate guidance and norms.

3. Exchange evaluation and solve problems.

Communication evaluation is a key link in the organic combination of teacher-led and student-centered. The main duty of teachers is to organize students to communicate effectively in mathematics, activate students' thinking and broaden their thinking. After clearing the train of thought, let the students choose their own algorithm. When students have their own ideas, let them further summarize and sort out the algorithm through group communication. Finally, through collective communication, the algorithm is clear.

4. Consolidate methods and expand thinking.

Students have mastered the method, but also continue to practice and deepen their understanding in application. In this link, arrange some basic questions for students to answer with the knowledge they have mastered, so as to consolidate the application. Some expanding exercises are also arranged to enable students to use their existing knowledge flexibly and solve problems from different angles, thus expanding their thinking and cultivating their application consciousness.