People's Education Edition "Compulsory Education Curriculum Standard Experimental Textbook"? Page 60 ~ 63 of the second volume of the third grade of mathematics.

Brief analysis of teaching materials;

"Area and Area Unit" is the first lesson in Unit 5, Book 2, Grade 3. The teaching of area and area unit is carried out on the basis that students master the characteristics of rectangle and square and can calculate the perimeter of rectangle and square. The length of primary school students' learning area is a leap in the cognitive development of spatial form. Learning this lesson well is not only conducive to developing students' concept of space, improving students' ability to solve simple practical problems, but also laying a foundation for learning the area calculation of other plane graphics in the future.

Teaching objectives:

1. Let students understand the meaning of area through the experience activities such as "Say and compare".

2. We can estimate and measure the area of the graph with the unit we choose, and realize the necessity of introducing a unified area unit. Understand the commonly used area units of square centimeter, square decimeter and square meter, and initially form the spatial concept of the actual size of these units and form the correct representation.

3. In the process of solving problems, let students feel the necessity of establishing area units and understand the law of establishing area units.

4. Cultivate students' observation ability, calculation ability, generalization ability and problem-solving strategies, so that students can realize that mathematics comes from life and serves life.

Teaching emphasis: make students understand the meaning of area, master the commonly used area units and establish the correct representation.

Teaching difficulties: make students establish the concept of area, establish the expression of area unit, and realize the necessity of introducing unified area unit in operation.

Teaching preparation:

Teaching AIDS: multimedia courseware, square centimeter, square decimeter and square meter teaching AIDS.

Learning tools: A set of learning tools with many squares, circles, regular triangles, square centimeters and square decimeters. Square paper with a side length of 1 cm.

Analysis of learning situation:

The study of this class is very operational for students. Therefore, in the whole learning process, students can't acquire knowledge by teachers' explanations, but acquire new knowledge through their own observation, operation, practice, thinking and discussion. For example, in the process of learning, we can intuitively understand and discover the size of the surface of the object by touching the familiar surface around us; On the basis of perceptual knowledge, the concept of area is revealed. In the process of swinging, measuring and counting, it is fully understood that the area of an object should be measured by a unified standard, and students' learning fully embodies the process of exploring and experiencing the formation of knowledge.

Teaching strategies:

This is a concept class, and the boring concepts must be intuitive and vivid, which is easy for students to accept. Therefore, in the teaching design, students should be more hands-on, more brains and more talks, so that students can feel the meaning of area and the meaning of area units and how to use them accurately. At the same time, through cooperative learning, every student has the opportunity to participate and show, and at the same time cultivate the ability of cooperation. In short, the teaching of the whole class is always based on the development of students, which reflects the subjectivity of students everywhere.

Teaching process:

First, create situations and introduce new lessons.

1. (Play the recording) Show the story of two generations of love and create a problem situation.

The story of two generations of love: One day, Master Bayi wanted to buy the yard of two generations of love to build a house, but he didn't want to spend too much money. He went to two generations of love and said, "Your yard always enjoys my shade, so you have to pay the shade fee." Afandi said, "Lord Bayi, where is the money? What should I do? " Master Bayi said, "Then sell me your yard!" Finally, the two generations signed a contract with Master Bayi: "Sell the 60 meters of his yard to Master Bayi at 10 yuan, and give the 60 meters of his yard to Master Bayi tomorrow, and never regret it!" This is to certify that. "The next day, two generations of love with bayi adults to 10 yuan smiled. Lord Bayi shouted "I was cheated by this contract".

2. Students, do you know why two generations of love laugh?

3. Students report on the camera blackboard: face.

Second, the perception of experience, the establishment of representation

1. Perceived area through the surface of an object.

Teacher: Many objects around us have their own faces: the cover of a math book, the face of a desk and the face of a blackboard.

Teacher: There are large and small surfaces of objects. Show me the math book. This is the cover of the math book. Touch it with your hands.

(student operation. )

Teacher: Now, please touch the desktop again and feel it. What students touch is a part of the surface of an object. (blackboard writing: the surface of an object. )

Teacher: What is the surface of an object? Show objects: Students perceive the surface of objects. )

Teacher: Compare the size of the textbook cover with that of desks, blackboards and desks.

List the faces of common objects in life, and tell which object has the largest face. )

Teacher: I just said the size of the surface of the object. We call the size of the surface of objects their area. (Supplementary blackboard writing: area size. )

2. Understand the area by closing the graph.

Teacher: Does the surface of the object have a size, and does the plane figure have a size?

Show me two pictures:

Teacher: Which number is bigger?

Students have different opinions. )

Teacher: Who can talk about their own reasons?

Student: The number 2 can be enlarged.

Teacher: (Q) Why?

Health: Because Figure ② is not closed.

Teacher: This word is well used-"closed" (click on the courseware, and the courseware will color 1). Graph 1 is a closed graph, its size is fixed and can be measured.

Teacher: What will happen if Figure ② is colored?

Teacher: (Click the courseware again, and a line is added in Figure ②, which is also closed. ) Can you judge now?

Teacher: Figure ② was originally unmeasurable, so it is impossible to determine its size. We can determine its size after it becomes a closed figure.

Health: (induction) the size of closed figures, that is, their area.

Blackboard: the size of the closed figure.

3. Summarize the meaning of area.

Teacher: Who can tell the area in their own words?

Health: The size of the surface or closed figure of an object is their area. (camera, blackboard book. )

Three, clear the necessity of a unified unit

1. Observe and think, explore and communicate.

Teacher: Through observation, we know the area between the blackboard surface and the desktop. The area difference between Figure ① and Figure ② is obvious, so it is easy to compare their sizes.

Teacher: The real thing is two rectangular pieces of paper with similar area.

Teacher: Who is the bigger and who is the smaller of these two pieces of cardboard? Students have three opinions: the same size, paper ① is big, paper ② is big.

Health: Fold them together and compare the sizes of two pieces of colored paper.

Teacher: (emphasizing method) overlapping method. Can you compare their sizes?

Health: It's hard to say whose area is big now.

Health: cut after overlapping and compare the sizes.

Teacher: Good idea. This method is called cut-and-paste method, which is often used to learn plane graphics.

Teacher: (Sticking two numbers on the blackboard) If I put them like this, I won't let you cut them or spell them. Is there any good way to compare their sizes?

Health: Measure, measure their length and width, and calculate their circumference.

Teacher: It's the circumference. Is the longer the circumference, the larger the area?

Health: Compared with the perimeter of the cover of the math book, the perimeter of the desktop is longer, so the area is larger.

Teacher: Is this the case in all cases? Please draw two different rectangles on the square paper prepared before class, with a circumference of 20 cm.

Summary: perimeter can't determine area. (Write it on the blackboard. )

Teacher: (Guide students to use learning tools to make a pendulum and measure it. ) Let's see who has the largest area.

Students work in groups. The teacher prepared a schoolbag for each group. There are circles, squares and triangles in the schoolbag. Specially prepare squares, circles and squares of different sizes for several groups of students. )

2. Explain the necessity of unifying units.

Teacher: Do you know the result?

Student: Our group has encountered difficulties, and the school tools are no longer used. One is round and the other is square. My tools don't work well either, big ones and small ones.

Teacher: (Stick the students' works on the blackboard. ) What did you find?

Health: It is more appropriate to use squares of the same size. Because there is a gap in the circle, the triangle is used too much and it is not easy to swing. One uses a circle, the other uses a square, and the graphics used are different, so it is impossible to compare the sizes. You must use squares of the same size.

3. Lead out the area unit.

According to the students' report, randomly guide the students to use a square with a certain size when comparing the surface areas of two objects. It is internationally stipulated that a certain standard square size is called an area unit. And guide students to know that it is most convenient to measure the area of an object with a square.

Teacher: (Summary) For the convenience of research, mathematicians have designated some commonly used units of area. What is the common unit of area? Please learn the content on page 63 by yourself and think about the following questions: What are the common area units? How are they stipulated? What objects in life are close to these area units?

Students teach themselves and teachers patrol. )

Teacher: From the reading just now, who knows what are the commonly used area units? (Teacher's camera blackboard: square centimeter, square decimeter, square meter. )

4. Know the area unit.

Teacher: Now the team chooses a regional unit to report.

Health: (report 1cm 2) A square with a side length of1cm has an area of1cm 2. The area of nails is close to 1 cm2.

Teacher: What other objects around us are close to 1 cm2? (Courseware demonstration) The switch button and a key of the computer keyboard are all close to 1 cm2.

Teacher: Let the students take out a small square with an area of 1 cm2 from their schoolbags.

Teacher: Measure the area of a rectangular piece of paper and put it with a piece of paper 1 cm 2 to see what its area is.

Teacher: understand 1 square decimeter.

Health: A square with a side length of 1 decimeter and an area of 1 square decimeter. The front of the pencil box and the cover of the math book are close to 1 square decimeter.

Teacher: Compare the size of 1 square decimeter with gestures. Please take out a square with an area of 1 square decimeter from your schoolbag. )

Teacher: Measure the surface area of the pencil case with a square of 1 square decimeter, which is about several square decimeters.

Teacher: The newspaper knows 1 square meter.

Health: a square with side length 1 m and area 1 m2.

Teacher: Can you find 1 m2 paper from your schoolbag?

Health: One square meter is too big to fit in the schoolbag.

Teacher: Do you want to experience the size of 1 square meter?

(Show a square with an area of 1 m2. Let the students guess how many students can stand. Let the students feel the actual size of 1 square meter through activities. )

Teacher: Think about it. How many square meters is this blackboard?

Fourth, comprehensive use, buckle back to the theme

Teacher: How many units of area do we know today? Which objects is each area unit suitable for? Teacher, here is a stamp. Which area unit should be used to measure? What if you want to measure the area of the desktop? What unit is used to measure the floor of the classroom?

Teacher: Back to the story of two generations of love, classmates, now do you know why two generations of love laughed?

Teacher: It seems that everyone knows and understands these three units of area. So, are there only these three area units? (Students make bold guesses. )

Verb (abbreviation for verb) sums up the harvest

1. What did you get from this lesson?

In this course, students use their knowledge and wisdom to solve problems in real life. I hope that students will continue to observe life from the perspective of mathematics in their future study, and I believe you will make greater discoveries.

Reflection:

First, let students learn and do math in real life.

Interest is the best teacher for students. At the beginning of the class, from the introduction of The Story of Two Generations of Love, let the students analyze why the two generations of love laugh, let the students think in the problem situation, and the students' enthusiasm will be fully mobilized in the first time. Students feel that mathematics is not far away from us, and they are all around us.

The construction of students is not the result of teachers' teaching, but through personal experience and interaction with the learning environment. What is "noodles"? I can't say clearly, but as long as I point, touch and compare, the students will know fairly well. Then touch the book cover and desktop in class ... feel the "face of the object" everywhere and initially establish the appearance of the face. In a large number of intuitive practical experience activities, students can really feel what "face" is. For the understanding of graphic area, I first showed a group of contrast graphics, which triggered students' cognitive conflicts, thus guiding students to realize that only closed graphics have area, and the size of closed graphics is called the area of closed graphics. Finally, it leads to a comparison between "the size of the object surface is called the area of the object surface" and "the size of the closed figure is called the area of the closed figure". Let the students say what is the area in their own words, sum up two sentences into one sentence, and then sum up the meaning of the area. This further deepens the understanding and mastery of the concept of area.

Second, strengthen the experiential learning of mathematics.

The process of learning is both a cognitive process and an exploration process. In order to make students experience the necessity of unifying area units, make mathematics knowledge a reality that students can see, touch and hear, and truly feel the true meaning and value of mathematics. When comparing the sizes of two figures, many contradictions are introduced to students, which makes them experience a series of activities from observation-guessing-verifying by overlapping method-splicing-splicing-arranging by unified standards-establishing area units, and students engage in thinking confrontation and gradually establish new knowledge. Students begin, use their brains, cooperate and communicate, show and report, and the classroom has really become a learning paradise for students to show themselves.

Third, cultivate students' self-study ability and problem-solving ability.

There is no need for students to explore the rules of area units. In this part of the teaching, let the students learn by themselves with questions, then report in groups and other students supplement. Through talking, watching, standing and other activities, we can fully perceive the actual size of the area unit and establish contact with a surrounding surface, thus helping to establish image memory. Let students choose the appropriate area unit to measure the surface in their life, which not only makes use of the learning results, but also closely follows the problem situation at the beginning of the class, so that students are full of pride and successful experience in solving problems. At the same time, through "are there only these three area units?" In this way, new knowledge will naturally come into being.

disadvantage?

It is also worthy of reflection and evaluation. The evaluation language is monotonous and lacks substantive evaluation such as mathematical ideas and methods. When each group chooses different methods to compare the sizes of two rectangles, it fails to seize the opportunity of infiltrating mathematical ideas and methods. The evaluation of group cooperation is not enough. The results of group cooperation are only reported by individual students, ignoring the participation of other members, only paying attention to the evaluation of the reported students, but writing off the contributions of other students, which is bound to turn the group activities into personal exhibitions, which deserves my reflection and efforts.

In a word, there are still many problems worth thinking about how to teach mathematics well in combination with the new curriculum standard. Through this lesson, I want to have a "living" concept class, so I need to keep learning, thinking and exploring.