Textbook analysis

The understanding of "area" is the content of the fourth unit of the third-grade experimental textbook of the compulsory education curriculum standard published by Beijing Normal University, and it is the new content in the new textbook. The study of this lesson is the concept of area that students first contact with, and area is the basis for students to learn the content of this unit. In order to let students understand the meaning of area more intuitively, the textbook arranges three different levels of practical activities: first, combining four specific examples of specific size, let students have a perceptual understanding of the area and initially perceive the meaning of the area; The second is to compare the area size of two figures and experience the diversity of comparison strategies of area size, so that students can initially feel the advantages of square measurement and comparison, paving the way for learning area units in the future; Thirdly, through drawing on paper, we can further understand the meaning of area and experience the mathematical fact that graphics with the same area can have different shapes.

According to the characteristics of textbook compilation, students' life experience should be fully linked in teaching. When students initially perceive the meaning of area, they should give examples to illustrate the size of the surface or figure of the surrounding objects, so as to enrich their perceptual knowledge of area, make students truly realize the close relationship between mathematics and life, realize the wide application of mathematics in life, and stimulate their enthusiasm for learning mathematics. The teaching of this course should also pay attention to the cultivation and development of the concept of space. The development of the concept of space can't rely on an armchair strategist, but must be based on students' own spatial perception and experience. All kinds of activities should be experienced by students themselves, so that students can consciously experience and feel in the real and vivid process, especially the activities of "evaluation" and "posing". Students can use school tools "stamps" and "coins" to fill rectangles and squares at the same time. In the teaching of this course, we should pay attention to cultivating students' innovative spirit and let them experience the joy of innovation. In the process of comparing two graphic areas, encourage students to find different comparison methods; When designing graphics on square paper, students are encouraged to design accurate and creative graphics, so that students can experience that innovation is a part of classroom study and life.

Student analysis

Students have a certain knowledge base and life experience before studying here. They have a preliminary understanding of three-dimensional graphics, such as cuboids, cubes, cylinders, spheres and plane graphics, such as rectangles, squares, triangles, circles and parallelograms. They can calculate the perimeter of rectangles and squares, and have accumulated some experience in understanding the surface size of objects in daily life. Have preliminary practical experience, be able to actively study problems, dare to innovate, have the ability to independently design research programs, have the awareness of cooperative learning and the initial ability of cooperative learning. Through the communication with students, I found that many students already know the word "area" and urgently need to learn about it. Some students already know the calculation method of rectangular and square area, but they can't explain the meaning of area clearly. It can be seen that it is difficult for students to establish a clear concept of "area" and it is easy to confuse "area" with "perimeter".

Therefore, in order to facilitate students' study, teachers have prepared a large number of learning tools (scissors, nickels, stamp pads, seals, transparent square paper, rectangular paper, square paper, etc.). ) Show it to the students before class. Teaching design attempts to guide students to understand the meaning of area by combining familiar examples and specific activities, and turn mathematical activities such as "comparison", "estimation", "swing" and "drawing" into real and vivid experience processes that students experience personally, and strive to implement the goal of cultivating and developing spatial concepts. In addition, in this course, students' problem-solving strategies are developed by comparing the areas of rectangles and squares. In the process of exploration, students can learn estimation methods, share their experience in solving problems with estimation, enhance their awareness of problem-solving strategies, and form a good habit of thinking about strategies when doing things.

learning target

1. With specific examples and drawing activities, understand the meaning of the area, and estimate and measure the area of the drawing with the unit of your choice.

2. Develop hands-on operation ability, intuitive estimation ability, spatial perception ability and cooperation and communication ability with others in activities.

3. Experience the process of comparing two graphic areas and actively explore, so as to experience the diversity of comparison strategies and the fun of innovation.

4. Experience the close relationship between mathematics and life, feel the magic of mathematics and stimulate interest in learning.

teaching process

First of all, create a situation and initially perceive the significance of this area.

1. Session Introduction

(The teacher writes "area" on the blackboard)

Students, have you ever heard the word "area" in your life? What do you think "area" means?

Organize students to exchange ideas.

(Teachers get to know students' existing knowledge and experience in the process of communicating with students)

② Evaluate according to the students' speeches.

Watch the courseware demonstration: a lawn full of grass and feel the area of the lawn.

(with the help of intuitive observation, the meaning of the initial perception area)

2. The size of the object surface

Touch the cover of the math book and feel its size.

Think about it, which objects around us have faces smaller than the cover of this math book?

Look, which items are bigger than the cover of this math book?

With the help of student associations, find out the "faces" of some objects. In the process of "touching", students have a preliminary understanding of "face" and initially realize that the face of an object has size and can be compared. In teaching, teachers consciously connect with real life and introduce familiar life examples to help students feel what "face" is with the help of their existing life experience, stimulate students' interest in learning, and at the same time let students realize the close relationship between mathematics and life, the application of mathematics in life and the value of learning mathematics. )

Summary: There are many such faces. We just compared "the surface of an object" (teacher writes on the blackboard: the surface of an object).

Let the students take out the soap box, choose two faces at random to compare their sizes, and let the students observe them with their eyes or touch them with their hands first, and then compare them.

After independent thinking, organize students to communicate.

With the help of the soap box, this link not only highlights the physical mathematical facts, but also implies the method of comparing the sizes of two rectangles, which plays a connecting role. )

3. The size of the closed graph

The teacher shows three figures and asks the students to identify them. (Teacher writes on the blackboard: closed graphics)

Choose two graphs at random and compare their sizes.

Reveal the concept

(After the students communicate, the teacher will finish writing on the blackboard:

The surface of an object

The size of or is their area.

Closed graph

When the teacher writes on the blackboard, please talk about the area. )

In order to make students have a clear and comprehensive understanding of the area, the teaching design is divided into two levels, from the surface of the object in real life to the plane figure, reflecting the cognitive process from universality to particularity and from generality to individuality. )

Teacher's explanation: We already know what area is, so we can use the word "area" when we talk about the size of a surface in the future. Can we do that?

Put forward clear requirements and consciously ask students to learn to express themselves in mathematical language.