Under the background of the new curriculum reform of education and teaching concepts, open classes must embody advanced education and teaching concepts, which means that teachers are facing new adjustments and challenges in every link of the teaching process. The following is my teaching plan "The Area of Rectangle" about the quality class of primary school mathematics. I hope everyone will read it carefully!

course content

Mathematics, the third grade experimental textbook of compulsory education curriculum standard (Volume II), published by Jiangsu Education Press, pp. 74-77.

Teaching objectives

1. Let students understand the meaning of area in activities such as observation and operation.

2. Let students experience the process of comparing the sizes of two graphs and experience various comparison strategies.

3. Make students experience the connection between mathematics and life in learning activities, stimulate their interest in learning and develop their initial concept of space.

teaching process

First, create a situation and introduce the game.

Teacher: Students, there are so many teachers coming to class today, so we welcome them with the warmest applause. Okay？

[Discussion: Clap your hands to introduce new lessons. 〕

Second, the initial perception, cognitive field

1. Reveal the meaning of area.

Teacher: When we clap our hands, the place where our hands touch is the palm of our hand. Who will touch the palm of a teacher's hand? (Students touch the teacher's palm)

Teacher: Where is your palm? Touch your palm. (Students touch their palms)

Teacher: (touching the cover of the math book) This is the cover of the math book. Which side of the teacher's palm is bigger than the cover of the math book?

Student: The cover of the math book is big, but the palm is small.

Teacher: Would you please finish what you just said?

Student: The cover of the math book is bigger than the palm, and the palm is smaller than the cover of the math book.

Teacher: Hold out your little hand and put it on the cover of the math book.

Health 1: The cover of the math book is bigger than my palm.

Health 2: My palm is smaller than the cover of a math book.

Teacher: Which is bigger, the cover of the math book or the appearance of the blackboard?

Health: The cover of the math book is smaller than the surface of the blackboard, and the surface of the blackboard is larger than the cover of the math book.

Teacher: (referring to the blackboard surface) Like here, the size of the blackboard surface is the area of the blackboard surface. (blackboard writing: area) Can you tell me the cover area of the math book?

Student: The size of the cover of a math book is the area of the cover of a math book.

[Discussion: Touch the teacher's palm, touch your own palm and the cover of the math book to observe the appearance of the blackboard. With the help of students' own familiar things and their own life experiences, students can fully feel and trigger the generation of new knowledge. When students are immersed in life experience, reveal the significance of the theme of this lesson-area. Summarize life experience into mathematical knowledge in time and upgrade life language to mathematical language: the size of blackboard appearance is the area of blackboard surface, and the size of math book cover is the area of math book cover. Firstly, the meaning of "area" is explained by concrete things, which lays the foundation for the formation of the concept of "area". 〕

Touch and say.

Teacher: There are many objects around us, such as desks, stools, exercise books, pencil boxes and so on. These objects have faces, and the areas of these faces are large and small. Now, please choose two of them to compare. Which area is large and which area is small?

Student 1: The desktop area of the class is larger than the stool area.

Student 2: The area of the cover of the exercise book is smaller than that of the desk.

……

[Discussion: Touch the appearance of surrounding objects and observe the appearance of tables, stools, exercise books, pencil boxes, etc. Comparing the sizes of two sides can deepen students' understanding of "the appearance of objects is large and small, and the sizes can be compared" and consolidate the concept of area. At the same time, axioms such as "total equal product" and "area additivity" can penetrate into equality with other axioms, which lays the foundation for introducing area units and directly measuring to find the area. 〕

Third, the operation experiment, compare the size

1. Paint it.

Teacher: We have studied the appearance of so many objects. We've seen them and touched them. Do you want to draw it again? (Thinking) Ok, divide the class into two groups and have a coloring contest. Please listen carefully to two requirements: first, the graphics sent to you should be drawn without gaps; Second, you can start painting only when the teacher says "start". The time is 1 min. Please ask the group leader to open the envelope 1 and give everyone a piece of paper. (The group leader gives each student a blank sheet of paper as required)

Teacher: Are you ready? Let's go

Students color.

Teacher: Time is up. Please raise your hand if you have painted it. Next, I solemnly announce the result of the game: the team won. The winning team, raise your works for everyone to see.

Health 1: It's so unfair! We don't believe it.

Health 2: The paper they draw is much smaller than ours.

S3: Look at our paper. Much bigger than yours.

Teacher: Your group's paper is big, but theirs is small. That's what your group wants to draw.

Health: The area to be drawn by our group is much larger than theirs.

[Discussion: Create interesting problem situations, make students form cognitive conflicts, and create a psychological state of "anger" and "depression". "We have studied the appearance of so many objects, seen them and touched them. Do you want to draw it again? Divide them into two groups and have a coloring competition. " The students are full of interest. However, the area of the two groups of color graphics sent by the teacher in advance is different. One group is smaller and the other group is much larger. Of course, it takes more time to draw. In this way, students will have a stronger feeling about the size of the area when they see the "truth". 〕

2. practice.

(1) Question 2: "Think about it and do it".

Show the graphics of four provinces depicted on the same map of China.

Teacher: This is a map of four provinces drawn from the same map of China. Can you see which province has the largest area and which province has the smallest area?

Health: Sichuan Province has the largest area and Jiangsu Province is the smallest.

(2) Draw graphs with different areas.

Teacher: Now, please get to work and draw two figures with different areas.

Students draw two figures with different areas according to their needs.

Choose 3~4 pictures to show on the projector, and compare the sizes of the two pictures.

Teacher: Can all these figures drawn by students compare the size of the area? (yes)

(3) "Want to do" question 5.

Show me the plan of the school.

Teacher: Let's look at the plans of another school. Choose two of them and compare the size of the floor space.

Health 1: the area of sports ground is larger than that of living area.

Health 2: The pool is smaller than the flower bed.

Health 3: The area of the office building is similar to that of the living area.

……

Teacher: Is the office building bigger or the living area bigger? Can you tell at a glance?

Health: I can't say for sure.

Teacher: How do you compare the areas of two figures that look similar in size? Let's look at the following example.

[Discussion: The size of the two regions with great disparity can be judged by observation. For two graphs with similar areas, we must find another way to compare the sizes. 〕

(4) Compare the areas of graphs.

Teacher: (showing squares and rectangles with similar areas) Which of these two figures is bigger? (Students have different opinions)

Teacher: It is difficult for us to make an accurate judgment just by looking at it with our eyes. Can you think of any other way?

Students discuss in groups.

Teacher: For the convenience of comparison, the teacher provided you with some information: 4 small squares, a piece of paper and a ruler. You can use these materials to find a way to compare their sizes.

Students work in groups and teachers patrol.

Organizational feedback. (omitted)

[Discussion: Problems are the driving force of heuristic teaching. When we grasp the problem, we grasp the breakthrough point of classroom teaching. When the teacher showed two figures with very close areas, it caused an argument among the students. At this time, students are thinking with problems, and the search for strategies has changed from "external pressure" to "internal demand" for knowledge. 〕

Fourth, practical application to solve problems.

1. "Thinking and Action" Question 3.

Show pictures.

Teacher: Which of the following four figures has the largest area? Is there a comparison method?

Student: Count squares!

Teacher: Then, let's compare the sizes of these figures by calculating the grid.

Students count the results in the book and write them next to each number.

Organize reports after students finish independently. There are differences when calculating the area of trapezoid, and the answer of a few students is 20 squares. )

Teacher: Which answer is correct?

Health: It should be 18 cells, and the four and a half cells of trapezoid add up to 2 cells.

Teacher: By counting squares, we know which figure has the largest area.

Health: The trapezoid has the largest area.

2. Show the following picture:

Teacher: Xiaoming paved the floor with square bricks, and there are two parts left unpaved. If you cover these two open spaces, which open space uses more square bricks?

Students discuss and exchange their ideas in groups.

Teacher: How many square bricks were used in each of the two open spaces?

Health: The first open space should use 16 square brick, and the second open space should use 18 square brick.

Teacher: How do you know?

Health: You can count empty squares.

Teacher: How can we make the number of spaces in these two pictures accurate?

Health: You can draw empty squares before counting them.

Teacher: You try.

Students operate before projection. (Draw a line and count the spaces)

Teacher: Which open space has a large area?

Health: The second vacant lot has a large area.

Teacher: How many square bricks do these two vacant lots need?

Health: 16+ 18 = 34 (block).

3. the game (guess).

Teacher: Do students like playing games? (Like) Ok, let's play a game. The rule is: students are divided into two groups and look at the graphics presented by the teacher respectively. One group of students can't look at pictures, while the other group can't.

Teacher: (showing a big figure divided into four squares) Look at the first group of students. How many squares are there in this figure?

Health: (Qi) 4.

Teacher: (showing a small figure divided into six squares) Look at the second group of students. How many squares are there in this figure?

Health: (Qi) 6.

Teacher: Let's guess, which group of students see a large area of graphics?

1: 6 cells are more than 4 cells, of course, the number of 6 cells is larger.

Health 2: Not necessarily. Maybe the graphic grid of 6 grids is small.

Teacher: Which figure has a larger area? Do you want to see these two characters? (Showing two figures) Why is the area of the 4-grid figure larger?

Give birth to 1: 4 grids, each of which is very large.

Give birth to a 2: 6 grid figure, each grid is very small.

Teacher: It seems that when comparing the sizes of two graphic areas by calculating the grid, the grid should be the same size. This small square dedicated to measuring area is the "area unit", and we will study it next time.

[Discussion: Comparing the size of the area can be judged by observation and intuitive thinking. For two graphs with similar areas, other methods are needed, such as overlapping method and counting square. Compare the area of two numbers by square, that is to say, the comparison of the area of two numbers comes down to the comparison of the size of two numbers. The textbook uses the third question of "think and do" to guide students to experience this method. In the following exercise, because there are no ready-made squares in the picture, students can compare the bricks next to them and count how many squares there are, or draw squares first and then count. This small square dedicated to measuring area is the area unit, so make necessary preparations for learning "area unit" in the next class. 〕

General comments

This lesson has the following three characteristics:

First, close contact with students' real life. Pay attention to creating vivid learning situations, so that students can play while learning, practice while learning, experience new knowledge in activities and refine new knowledge in solving problems. On the basis of thoroughly understanding the intention of compiling textbooks, teachers use a wide range of curriculum resources and choose familiar cases as teaching content. Only in this way can we stimulate students' interest in learning, let them feel the close connection between mathematics and life, realize the expected teaching goal of the textbook, and make mathematics class come alive.

Second, strengthen the teaching of the concept of area. "Noodles" is an undefined concept in primary and junior high schools. In teaching, it is easy for students to confuse area and perimeter. Regarding area measurement, students should first master the direct measurement method of area (that is, the method of several squares) according to the concept of area and the meaning of area unit, and then deduce several area formulas to make the transition from direct measurement to indirect measurement. Therefore, in the teaching of the concept of area, we should pay attention to the axioms of "congruent product" and "additivity of area" to lay a good foundation for direct measurement. In order to prevent confusion between "area" and "perimeter", students are often trained by comparing problem groups.

Third, pay attention to grasp the opportunity of exploration, give effective guidance to students, and make students become the masters of learning. Teachers provide students with a space for active thinking and cooperative communication, and from time to time guide students to gradually form their own understanding of mathematical knowledge and effective learning strategies in the activities of observation, operation, guessing, verification, reasoning and communication. The teaching plan of open class should pay attention to perfecting concepts, methods and laws from solving problems, and give full play to the role of activities.

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