Teaching content: Beijing Normal University Edition, Grade Three Mathematics (Volume II), pages 39 ~ 4 1.

Analysis of teaching materials

"Area" is the content of "space and figure" in mathematics curriculum standard. The content of this lesson is to help students initially establish the concept of area. It is based on students' understanding of plane graphics, their characteristics and their ability to calculate the perimeter of rectangles and squares. In order to make students understand the meaning of area more intuitively, the textbook arranges three different levels of practical activities: first, through the "comparison" with four specific examples, the meaning of area is preliminarily perceived; Secondly, through the actual operation of comparing the area size of two graphs, experience the diversity of strategies for comparing the area size; The third is to draw pictures on square paper, to further understand the meaning of area, and to experience graphics with the same area, which can have different shapes. A large number of "comparisons", "guesses" and "swings" provided in the textbooks will become the activity process that students experience in class. According to the characteristics of teaching content, I created a challenging activity situation covering knowledge content, enriched students' practical activities and implemented the goal of cultivating and developing spatial concepts.

Student analysis:

"What is area" is related knowledge arranged on the basis that students already know the length units such as centimeters and meters, know the perimeter and can calculate the perimeter of rectangles and squares. The meaning of area, for the third-year students in the next semester, although the knowledge is new, the children have already had some life experience in their usual life accumulation; For example, the area of home housing, the area of our national territory and so on. However, these experiences are scattered and uncertain, and most students have no exact concept of the meaning of area. Therefore, students should intuitively understand the meaning of area and accurately compare the size of area, so they should pull back to the original starting point for teaching.

Teaching objectives:

1, combined with specific objects and activities, understand the meaning of area and compare the size of area.

2. Experience the diversity of comparison strategies by comparing the sizes of two graphs.

3. In learning activities, experience the connection between mathematics and life, exercise mathematical thinking ability, develop spatial concepts, and stimulate interest in further learning and exploration.

Teaching emphasis: understand the meaning of area.

Teaching difficulty: learn to compare the size of the surface of the object with the size of the plane figure.

Preparation of teaching AIDS and learning tools: courseware, square paper, rectangular paper, scissors, ruler, square paper, 1 coin,150 coin, and small pieces of paper with a side length of 1 cm.

Teaching philosophy:

The concept of area is abstract, which will be difficult for students to understand. In order to let students better understand and master the abstract concept of "area", I start with life, let students feel the size of the surface of the object by looking and touching, reveal the area of the object by comparing the size of the surface of the object, and let students connect the abstract concept with concrete examples in life to deepen their understanding of the area. Then the surface of the object in real life is gradually abstracted to the size of the closed figure, so that students can know the area of the closed figure, which is deep and interlocking, and students will understand the meaning of the area unconsciously.

In the process of exploring and comparing the sizes of the two figures, a space for students to engage in mathematics learning activities and exchange is created. Through the methods of exploration, communication and comparison, the size of the area is compared, and the teacher guides it in time, so that every student has the opportunity to express his ideas and make inquiry learning implemented. In this way, students fully and actively participate in the learning process, so that different students can get different development in mathematics learning. In practice, students have experienced the whole process of knowledge formation, deepened their understanding of the meaning of area, cultivated their ability of analysis, comparison and cooperation, and infiltrated the strategic consciousness of solving problems to some extent.

Teaching process:

First, create situations and introduce new lessons:

(Courseware demonstration point)

These are two vegetable fields. The lion king wants to give these two plots to goats and foxes. The honest goat let the fox choose first, and the fox quickly chose the first piece of land. Why? (The first piece is big)

Teacher: What does "the first big one" mean? What language should be used to describe it in mathematics? After learning today's lesson, I believe you will use mathematical language to describe it.

Second, the exploration of new knowledge:

1, the concept of perceived area:

(1) Know the surface of an object

Show: (a math book) This is an object. (Touching the cover of the math book) See what the teacher touches? (The cover or surface of a math book) What other object has a surface? Who can give an example and touch it?

Everything has a surface. For example: the surface of the blackboard, the surface of the table, etc.

(2) the size of the object surface

A, please observe the blackboard surface and the table surface. Which surface is bigger and which surface is smaller?

B, please take out 1 yuan coins and 50 cents coins prepared before class. Whose face is big and whose face is small? How do you compare?

Summary: Through observation, operation and comparison, we know that objects have large and small surfaces, and we call the size of the surfaces of objects their areas. For example, the size of the math book cover is called the area of the math book cover, and the size of the desktop is called the area of the desktop. Who can describe the area of some objects in life like a teacher?

Comments: Make use of the things around students, let students feel the existence and size of the area through touching and talking, and naturally transition to the meaning of teaching area.

(3) abstract closed graph

A, "closed graph" is abstracted from the above graph.

Teacher: What is the picture on the cover of the math book? Please draw this figure along the cover of the math book.

(courseware shows graphics) Say, what are these graphics?

Teacher's Note: These figures can all be called "closed figures" (blackboard writing: closed figures).

The teacher asked: What does "closed" mean?

Ask the students to answer, and the teacher finally summarizes the students' expression language.

B. (Courseware display topic) Which of the following figures are closed figures? Which ones are not?

Ask the students to answer.

(4) the size of the closed graph

Look at the characters in the picture. Who is older and who is younger?

Conclusion: This shows that closed figures also have dimensions. The size of closed figures is also called their area.

(blackboard writing) for example; The size of a rectangle is called its area. The size of a square is called a square.

Area. Who can describe the area of some closed figures like a teacher?

Comments: Abstracting the "closed figure" in the object shows the process of "mathematical knowledge comes from life", which enables students to sublimate their knowledge from perception and form abstract concepts; Students explain the meaning of "closure" in children's language, which makes the abstract concept easier to understand. Judging the practice of closed graphics in time can consolidate students' understanding of closed graphics, make their understanding more in place and make their concepts clearer.

(5) Summarize the concept of area.

Teacher: What do these two sentences tell us? Can you combine these two sentences into one sentence?

Ask the students to answer, and evaluate, modify or supplement the rest. The teacher finally summed up the concept of area. (blackboard writing: the size of the surface or closed figure of an object is their area. )

Comments: In abstract generalization, students not only realize the benefits of optimizing knowledge, but also experience the concrete process of sublimation of life-oriented mathematical knowledge into mathematical mathematical knowledge.

(6) Give examples to enrich our understanding.

Now please give an example to illustrate the size of the curved surface or closed figure of the object around you. Let the deskmate talk first, and then organize the students to communicate with each other in class. )

Everyone knows what an area is, so please see which statements are related to the area (courseware display). Which of the following statements relates to this area? Put "√" in brackets.

1. The size of the playground. Height of the basketball stand () 3. How big is the class table () 4. The size of the swimming pool. How much does the apple weigh? How tall is Xiaoming. How big is this glass ()

2. Experience in comparing area sizes with tools.

(1) Create cognitive conflict:

Secret exploration game: Brave children like to play secret exploration games. Here are five numbers, and the secret lies in one of them. Do you want to know which number it is in? The teacher gave you some hints and ruled out some wrong answers. Please listen carefully:

(1) This gift is not in the largest figure. Who should be removed?

(2) It is not in the smallest picture. Who should be removed?

The second hint is that it is not in the circle either. What do you know from this hint?

(4) Another hint: In the larger of the remaining two graphs. Guess where it is?

Answer the results by roll call. When students have different opinions, guide them to understand that it is difficult to compare the sizes of two figures through observation. At this time, we will use scientific methods to verify.

(2) Discuss the method of comparing area size:

Who is the bigger and who is the smaller of these two numbers? Take out the rectangles and squares you have prepared, and with your help.

Holding small disks, squares, rulers and other tools in their hands, the students in the group worked together to find ways to compare their own areas. Pay attention to group cooperation, listen carefully when others say, compare with each other, and see which group is in good order and which group has more methods.

B: group discussion, communication and teacher's patrol guidance.

C: class exchange.

Just now, with the help of tools, we compared the areas of rectangles and squares. The teacher actually thought of several methods. Would you like to have a look (courseware demonstration)?

Students are really capable. As long as you use your head, you can come up with more and better methods. Which of these methods do you think is better? Why?

Conclusion: These methods are very good, so we should use them flexibly according to the actual situation.

Comments: In the process of comparing the size of graphics, students have gained many methods, highlighting the diversity of problem-solving strategies. Focus on guiding students to understand different comparison methods and feel the advantages of squares in comparison.

In the process of cooperation and communication, everyone's ideas become a kind of curriculum resources, which complement and improve each other in the process of communication, constantly absorb other people's views and realize resource sharing. This kind of resource enjoyment not only simply solves the problem of knowledge, but also enables students to feel the joy of cooperation between people and enjoy the joy of positive thinking and success in the process of communication.

Third, the happy practice room

Students all know that you should pay attention to exercise at ordinary times, so that your body will be healthy and your study will be healthy. When we study knowledge, we should pay attention to the application of knowledge, so that our knowledge can be more solid. Next, let's take a look at some projects in the Happy Training Room. (Courseware demonstration)

1. Which figure in the grid has a large area? (textbook page 4 1 question 2)

2. Say that the area of each color figure is equal to the size of several small squares. (textbook page 4 1 question 3)

3. Which figure has a large area? (textbook page 4 1 question 4)

4. Draw a picture on the square paper.

Teacher: The students are very serious. Let's have a creative competition. Please open page 40 of the textbook and draw a picture: draw three figures with an area equal to 7 squares on square paper, and compare them to see who draws accurately and creatively.

(Student operation, teacher patrol guidance)

(Work display, exchange evaluation. )

Teacher: What did you find through this activity? How do you feel? The graphics they draw are all seven squares, but the shapes are different. )

Summary: That is to say, the shapes of graphs with the same area may be different.

So are the areas of the figures with the same number of squares the same? (Courseware demonstration)

These two figures have the same number of squares, but are their areas the same?

Summary: Calculating the grid size is the basic method to compare the graphic area, but the prerequisite for using this method is that the grid size must be uniform.

Comments: Entertaining education through fun, infiltrating mathematics knowledge into game activities, so that students can learn while doing, and in game activities, students can easily and happily understand mathematics knowledge unconsciously.

5. Brain Training Camp (Outward Bound Exercise)

The floors of our classroom and bedroom are paved with two different types of floor tiles, and both rooms are made of 100 bricks. Are these two rooms the same area? Why? The square brick area in the classroom is large, but the square brick area in the bedroom is small.

Comments: The practice is progressive and has a slope. In practice, the meaning and comparison method of area are further consolidated; The demonstration of dynamic courseware vividly shows the concrete operation process of comparison strategy and excavation and filling method, which expands students' knowledge and improves their comprehensive practical ability.

Fourth, the class summary:

What did we learn today? What did you get? (student summary)

Teacher's summary: Students, this class has done well, and everyone has gained something. Let's praise ourselves. Students who think this class is doing well say to themselves: My class is doing well, I am great! Students who think their performance is not good enough should work hard in the future.

Blackboard design:

What is the area?

The surface of an object

Or size, is their field.

Closed graph

Teaching reflection

This lesson introduces the learning content with something familiar to students-math books, and organically combines the meaning of direct feeling area with students' life experience. Strengthen students' practical experience. Through "guessing", "comparing" and "drawing", students are provided with a lot of practical opportunities, making the classroom a vivid process for students to experience personally, and students' spatial concept has been effectively cultivated and developed.