"Chickens and rabbits in the same cage" is the wide-angle content of the second volume of mathematics in grade four. The editor's ideas are very high. On the one hand, it can guide students to understand the ingenious ideas of the ancients to solve such problems, feel the wisdom of their ancestors and stimulate students' interest in mathematics. On the other hand, students are encouraged to experience the process of solving problems through trial and hypothesis, and their inductive reasoning ability is cultivated. In the specific arrangement, the textbook of 20 14 has been greatly adjusted compared with the experimental textbook, from the sixth grade to the fourth grade, because this content is not challenging enough for the sixth grade students, and learning to solve problems in the fifth grade will also cause some interference to the learning list method and hypothesis method. Therefore, this textbook revision arranged it in the fourth grade, deleted the equation solution, and highlighted the hypothesis method and the list method. Through the process of "hypothesis-verification-adjustment ……" to finally find the answer, I realized a strategy to solve the problem: simplify the complex-find the law-solve the problem. Through the study of this lesson, it is not only conducive to improving students' ability to solve problems with mathematics, but also conducive to feeling the wonder and function of mathematical thinking methods. At the same time, they are trained in mathematical thinking and gradually form the habit of thinking in an orderly and rigorous way.

Textbooks provide very rich materials. Firstly, it leads to the problem of chickens and rabbits in the same cage recorded in Sun Zi Shu Jing, and then presents the inquiry process that allows students to go through from guessing to list method and then to hypothesis method to solve problems. In addition, the ingenious solutions of the ancients in "reading materials" are introduced to expand students' thinking of solving problems. Specifically, it presents the following characteristics.

(1) In the arrangement, the equation method is deleted and the hypothesis method is highlighted.

(2) From the method point of view, it presents a variety of problem-solving strategies.

(3) From the application point of view, it enriches the types of "chickens and rabbits in the same cage"

Second, thinking about classroom practice

When teaching for the first time, Mr. Li deliberately presented a variety of methods, each of which had complete feedback, which led to a little tight time allocation. Some students are skilled in drawing in class because of their poor understanding ability, so the following communication formulas are difficult to understand. Secondly, the mathematical model, more importantly, let students understand and master the methods to solve such practical problems through the model, and adjust their mathematical thinking and methods by communicating the connections between different situations and using assumptions. It is precisely because of the high thinking content of the learning content itself that children often have certain learning difficulties in the learning process, which is difficult to fully grasp. Some children will feel helpless once they encounter variant questions. This is far from teacher Li's expectation and the conception of the textbook.

After discussion and consideration, we think we should:

1. Reasonable selection of teaching content

Every method in the textbook is explained in every way, and we dare not choose it, which directly leads to the shortage of classroom learning time. Judging from the learning effect, students always have the help of teachers and classmates in the classroom, which seems to be positive and smooth, but the time for students to think independently is not sufficient, which leads to students' lack of basic methods, understanding the ins and outs of hypothesis method and the thinking behind drawing method and list method.

2. Diagnose and master students' learning situation.

The premise of teaching should be to understand the starting point of students' learning. In fact, the starting point of children's teaching in the class is uneven. Some children try to solve the problem by "spelling"; Some children can use "painting" to express the process of solving problems; Some children have been exposed to the formula of cage-free chicken in the training class in advance, but they don't know the reason for this formula. How to effectively use and connect children's existing experiences? Teachers need to present materials and methods in an orderly way, and constantly communicate between methods.

3. Deeply understand the learning principle

In class, teachers need to guide students to understand the similarities and differences between list, drawing and table calculation, so that children can understand the "origin" of table calculation and master the ideas and skills of solving problems, which should be the key teaching content of this class. At the same time, let students fully feel the practical problems similar to their own structures, move from one problem to another, and initially establish ideas and methods to solve such problems.

Thirdly, reconstruct the study plan and practice again.

(A) Reconstruction of the teaching plan

After thinking, Mr. Li has determined the following structure: based on the students' pre-test, understanding the students' existing starting point, making full use of students' works and connecting with their experience, and teaching on this basis. Focus on the connection between "drawing method" and "calculation formula solution", so that children can deeply understand the origin of "hypothesis method" and pay attention to the choice of learning materials. The essence of sharing a cage with chickens is to solve problems. Start with the materials that students are familiar with, first establish a model to solve the problem, and then communicate with other practical problems.

(B) change the teaching path

Pre-class preparation: (Teachers assign tasks for students to finish independently, so as to understand the real starting point of teaching)

1. Combined with picture books and current situation.

Use picture books to firmly grasp students' attention from the beginning. Guide students to understand deeply.

2. Show your work and feel * * *

? Show students how to use tables to solve problems and experience the process of "hypothesis-verification-adjustment" to find answers.

3. The principle of "three-single combination" and "groove-joint combination"

Carefully designing the study list and communicating formulas and reasoning in depth also avoid the teaching mode of teachers constantly helping students. Students study in the same mode, which embodies the main position of learning.

4. Feel the essence with variants

The exercise design has changed, and middle school students deeply feel the essence of the problem of chickens and rabbits in the same cage in the process of change and unchanging.

(3) Feel new experiences

Judging from the classroom effect, due to the reasonable choice of teaching materials and learning methods, and based on the students' pre-test, children are full of interest in learning and always maintain the enthusiasm of thinking, communicating and exploring. Because the teaching focus is clear, the rhythm is clear, and the classroom teaching time is effectively used, students have a deep understanding of the relationship between planning and column solving, and have gained something. Once again, we realized: "There are children's designs in our eyes, so we need to seek relevant materials and build a focused teaching."

Generally speaking, this teaching and research is a valuable learning experience for instructors and participants, which not only sharpens the teaching technology, but also improves the conceptual quality.