Grade 4 "Mathematics Wide Angle Pancake Problem" Lesson Review Draft

Fourth Grade "Wide Angle Mathematics Pancake Problem" Lesson Review Draft Part 1

After listening to the lesson "Pancake Problem" taught by Teacher Li, I was quite touched.

I think Teacher Li’s teaching has the following highlights, which are worthy of my study:

1. Introduction of situations, mobilizing students’ enthusiasm and revealing the topic.

Use the daily scenario of boiling eggs to introduce it. It takes 5 minutes to boil one egg. How many minutes does it take to boil six eggs? Some students said 5*6=30 (minutes), and some said 5 minutes. This naturally led to the focus of today's teaching, the selection of the optimal solution.

Two: Pay attention to students’ hands-on ability. When teaching the pancake problem, Teacher Li asked students to take out pre-prepared circular pieces of paper to simulate the pancake process. Students can experience the practicality and life style of mathematics through hands-on operations, and it can help them better choose the optimal solution. .

Three: Give full play to the team's ability to unite and collaborate, allowing students to truly become the masters of the classroom. When exploring the optimal solution for three pancakes, the teacher hands over the class to the students. Let the students make some moves with their hands, then fill in the form, and finally the team leader reports the results. In a series of activities, teachers let students go and carry out the activities. Teachers only provide necessary guidance, which fully reflects the student-centered thinking.

Four: Teachers are good at guiding and educating students. Finally, the teacher organized students to observe the form carefully and encouraged students: "What did you find?" Let students speak freely and diversify students' thinking. In the classroom, some students discovered at a glance the rule that "the number of cakes increases by 1, and the number of minutes increases by 3", but no students came up with the method as explained in the teaching reference book. The teacher gave timely guidance. If the number of cakes to be baked is an even number, just bake 2 sheets and 2 sheets. If the number of cakes to be baked is an odd number, you can bake 2 sheets 2 sheets first, and finally 3 sheets. Bake the cakes according to the best method above, which saves the most time."

Suggestions:

1. When the group reports on the problem of baking 3 cakes, it is necessary to make it clear 3 The teacher may wish to write on the blackboard the front and back of the cake to facilitate students' understanding in the next step.

2. When the team leader reports, the teacher should give students the opportunity to fully express their thoughts. After finishing speaking, the teacher will explain and guide again, and should not rush to interrupt the students' thoughts.

3. When doing group activities of four, I found that basically only two people in each group participated, and the other two people participated. The teacher did not participate in it. The teacher might as well conduct the activity in pairs and try to give each student a chance to do it. After making three cakes, the teacher asked the classmate to talk about the best plan just now. I think it is a bit restrictive. Students’ thinking should allow students to think about problems in their own way.

4. When teaching, I think teachers should guide and instruct the optimal plan in a certain order: “How many cakes should be baked. - How many sides should be baked on a piece of cake - no more than two sides at a time, and at least a few times - and finally calculate the number of minutes required. This step-by-step method is easier for students to accept, and it is also conducive to students' final understanding of the rules.

5. When the final rule was presented, I thought that the rule "number of cakes * 3 = number of minutes" is actually simpler, more intuitive, and more in line with their understanding characteristics. Students will divide the number of cakes into odd and even numbers. I feel a sense of confusion in the fourth grade "Mathematics Wide Angle Flapjack Problem" Lesson Review 2

"The Flapjack Problem" is the fourth grade "Mathematics Wide Angle" in the "Compulsory Education Curriculum Standard Experimental Textbook" published by the People's Education Press. content. Mainly by discussing how to rationally arrange operations to save time when pancakes are made, students can experience the application of optimization ideas in solving problems. Although pancakes are a common household chore in our daily lives, they contain mathematical problems and Mathematical thinking is profound. The purpose of organizing the textbook is to let students try to find the optimal solution from multiple solutions to the problem through simple examples of pancakes in daily life, so as to penetrate the idea of ??optimization into students and let them experience the overall thinking. Its role in daily life makes students feel the charm of mathematics.

1. Go straight to the topic, introduce new lessons, and reflect the beauty of simplicity

In this lesson, the teacher started teaching with the clue of "each classmate bakes a cake" and grasped the Due to the curious nature of students, we designed a "pancake" life scenario to directly reveal the topic and introduce new lessons. This not only allows students to understand the content of this lesson, but also quickly focuses their attention and stimulates students' interest in learning mathematics. It is simple and clear, and reflects the simplicity and beauty of mathematics.

2. Pay attention to questioning, highlight details, and reflect the beauty of details

Teacher Fang pays special attention to questioning details in this class. He can listen carefully to students' words and respond to students' vague questions. Always ask, ask when students don’t understand, ask when breakthroughs in important and difficult points are made, and ask every opportunity when the lesson is being generated. Pay attention to generation and guidance. From the questioning, we can see Teacher Yu’s art of guidance and pursuit of mathematics. The details are beautiful.

3. It has effectively broken through the teaching difficulties of the textbook and penetrated the idea of ??optimization.

At the beginning of the class, Teacher Fang made good use of the method of baking one cake and two cakes, and asked the students: Why does it take the same time to bake one cake and two cakes? This enables students to initially establish the concept of saving time by frying two pancakes in one pot at the same time. Then the focus was on discussing the method of making three pancakes with students. During this process, students were organized to discuss, report, and demonstrate at the same table, and then the students discussed, formed a plan for pancakes, displayed the students' plans, and compared the differences between the two plans. point to achieve optimization of the plan. The method of baking 3 pieces of cake is the key and difficult point here. Let this problem be discussed, cooperated, and explored by students. After solving the problem, then use the table to find the time for counting 4 pieces, 5 pieces,... these pieces of cake. The purpose of this treatment is to reduce the difficulty of the questions, help students think and solve problems, and then guide students to observe the table and discuss which is more convenient, the ordinary soldering method or the quick soldering method? "What did you find?", allowing students to choose the best plan through observation and comparison, and finally concluded that the number of cakes × the time required for one cake = the time required for the number of cakes. The entire pancake making process progresses step by step, cultivating Students’ mathematical thinking. Fourth grade "Mathematics Wide Angle Pancake Problem" Lesson Review Draft Part 3

Pancake is a mathematics lesson that infiltrates the idea of ??overall optimization. It infiltrates simple optimization ideas through simple optimization problems. In the teaching design and teaching process, pancakes are taken as the theme and the learning of mathematical thinking methods is the main line. How can pancakes be eaten as soon as possible? Start teaching. Designed an exploration process for baking 1, 2, 3 cakes - single and double cakes. Using the method of baking three cakes as a breakthrough point in teaching, students will develop the awareness to find the best solution from a variety of solutions, and provide students with time and space for independent thinking, hands-on operations, collaborative exploration, and display and communication. Students used small discs in their hands instead of cakes, and experienced the process of posing mathematical problems, solving mathematical problems, discovering mathematical rules, and constructing mathematical models. The whole lesson permeated the following concepts:

1. Let students practice and practice

The "Course Standards" points out: students' mathematics learning content should be realistic, meaningful and challenging. During the class, the teacher asked the students to use round pieces of paper instead of pancakes, and they performed pancake activities with their classmates. This link allows students to participate in the knowledge generation process, perceive in operations, and sublimate in practice. Students were also asked to use school tools to simulate pancake making at the same table. One person pancaked the pancake and the other recorded it.

2. Open up and allow students to speak freely

During class, the teacher asks students to work in groups to communicate, demonstrate, and then communicate with the whole class. This link realizes the communication between students and students. , an equal dialogue between teachers and students. It is both an interaction between students and students and an interaction between teachers and students. Learn from each other's strengths and weaknesses through mutual exchanges, constantly improve one's own cognitive system, and form a structured and regular knowledge structure. When studying how long it takes to bake 3 cakes (this is the focus and difficulty of teaching this lesson), no one has ever used the method of baking one cake and one cake. There are more methods of baking two cakes and then baking one cake. Some groups thought Alternate pancake method.

The teacher asked the students to demonstrate and explain, and everyone basically understood it. Later, they all knew to make full use of the condition of being able to bake two cakes at a time.

I think if this class can give children another developmental class, what if there are 4 cakes, 5 cakes and N cakes to bake at the end of the class? What did you find. Directly discover the rule that the number of cakes 3 = time, and the result is: if the number of cakes to be baked is an even number, just bake 2 sheets and 2 sheets. If the number of cakes to be baked is an odd number, You can bake 2 and 2 cakes first, and bake the last 3 cakes according to the optimal method above. This will save the most time. The students' findings are actually simpler and more intuitive. Mathematics teaching is not only the result of imparting knowledge, but more importantly, the process of exploring the formation of knowledge. It is not only a place to carry mathematical knowledge, it is also a place for students to develop in an all-round way. Only by continuously strengthening learning and continuously improving professional skills can teachers Give students an innovative classroom and a developmental classroom.