1. Show the situation diagram and find out the conditions (design intent: ask students not to answer questions in the form of reading, but to refine the requirements, be as concise as possible, and learn to extract effective mathematical information from life situations).

? Students in the class have successfully discovered the hidden information in the picture of "every bookshelf has four floors". The trend-oriented teacher: To solve problems in graphic form, we should not only pay attention to the information in the text, but also be good at discovering the hidden information in the picture.

2. According to the three conditions found, choose two related conditions, and put forward the parallel solution of mathematical problems. (Design intention: guide students to learn to analyze conditions and learn how to analyze topics from conditions)

3. Upgrade difficulty, ask a question according to three conditions. Students always ask, "How many books are there on the first floor?" The teacher asked, "How many books are there on each floor of the two bookshelves?" (Design intent: emphasize the accuracy of mathematical language and avoid ambiguity)

4. Students answer independently. Write it on page 13 of the math book. Basically, you can answer smoothly. Teacher's camera reminder: Can you think of other ways to solve the problem? (design intent: encourage students to think more and develop their thinking)

Some students can think of two ways, the whole class feedback, encourage students to explain their own problem-solving ideas (what is each step) and rewrite the comprehensive formula.

Teachers at the same table exchange solutions to problems with each other. Teachers give timely guidance and ask questions at random.

5. check. The teacher wondered: Is there "an average of 28 books on each shelf"? How to check whether our calculation is correct?

? Both classes successfully spoke out the test methods. In particular, the exam in the form of "reverse push" may be previewed by these students in advance. At this time, the teacher asked the camera: "Why can I take this exam?" What is each step? (Design intention: Help students to clear up their inspection ideas and deepen their understanding)

? The teacher concluded that this test method of "substituting points into original questions" actually takes the problem to be solved as a condition and the known 224 books as a question to calculate whether there are 224 books on a shelf.

Encourage students to write the examination method on page 14, and the examination idea should be consistent with the problem-solving method written on page 13.

6. Review and reflection

Think back to the thinking process and build a model.

Find conditions and problems-analyze quantitative relations-solve in one column-test.

7. Compare the similarities and differences between the two methods.

Further clarify the problem-solving ideas.

Question: Do we analyze this topic from the perspective of conditions or from the perspective of problems? The students in the class said in unison: "Analyze from the conditions".

Lead to the topic (lens introduction, in fact, is the "normalization problem")

Teacher: As long as it can help solve the problem, it is feasible to analyze the problem or condition. Different problems are solved in different ways.

One class can only explain this example, and time is still tight.

Insufficient: Students are a little confused about the problem-solving test after study.

Improvement: In practice class (one class only deals with two problems), I circle the problems into conditions and other conditions, turn the known conditions into problems, and mark them with question marks to help students understand the problems to be solved. In fact, the process of investigation is equivalent to solving a new problem. And ask the students repeatedly what is calculated in each step.

Disadvantages: teaching new courses and practical courses are based on conditions to analyze and solve problems, showing little problem. In the future, let students make statements independently, and meaningless formulas appear, which shows that some students just apply methods mechanically. After analysis, it will be easier and clearer to analyze some topics from the perspective of problems.

Improvement: the strategy of guiding children to solve problems should be flexible and cannot be analyzed from the conditions. You can choose to analyze the problem, and maybe there will be a new world.

Regarding this class, I have been slowing down and focusing on students' problem-solving ideas. However, in the subsequent process of doing the problem, students will still encounter various difficulties in solving the problem, but I still think that the process of problem-solving thinking is necessary and a process of continuous accumulation.