People's education printing plate sixth grade mathematics volume II "shape enlargement and reduction" teaching plan.

Enlarging and Reducing Graphics Teaching Plan (1) Teaching Objectives

1. Knowledge and skill goal: Understand the meaning of graphic enlargement and reduction; You can draw enlarged and reduced figures on square paper according to a certain proportion; Experience the similarity of graphics by zooming in and out. 2. Process Method Objective: To experience the method of enlarging and reducing graphics through mathematical activities such as observation, understanding and hands-on operation; Cultivate students' spatial concept and hands-on operation ability. 3. Emotional attitude goal: to stimulate students' interest and curiosity in learning mathematics, so that students can actively participate in learning activities and feel the joy of success in the learning process.

Emphasis and difficulty in teaching

Teaching focuses on understanding the enlargement and reduction of graphics.

teaching process

First, create situations and introduce new lessons.

1, observation experience.

Have you ever seen the following phenomenon? Somebody describe it! Show multimedia courseware, 56 pages of life situation map. Some of these phenomena in life enlarge objects, and some shrink objects.

2. Students give examples and speak freely.

Teacher: Have you seen other phenomena of enlargement and reduction in your life? Say its name. Teacher: It seems that the phenomenon of zooming in and out is still very common in all fields of our lives. These phenomena also contain some mathematical knowledge. Shall we study together in this class today? Zoom in and out of graphics? . Write on the blackboard.

Second, explore new knowledge.

(A) the perception of graphic amplification.

(Multimedia display of plane graphics on square paper, Example 4. )

1, the initial perception of plane graphics drawn on grid paper. Teacher: We already know a lot about plane figures. The teacher drew squares, rectangles and right triangles on the grid paper.

Let's look at three pictures drawn on square paper. What relevant mathematical information can we get?

Students talk freely in groups. A square is three squares long, a rectangle is six squares long and a right triangle is three squares wide.

2. Understand the requirements.

(1) multimedia drawing example 4 requires 2: 1 to draw an enlarged picture of this drawing.

(2) press? 2: 1? What does enlargement mean? Let the students express their understanding first, and then the teacher will explain. (Press 2: 1 to enlarge, that is, each side is enlarged to twice the original size. )

3. Understand painting by drawing a square.

(1) So how can we enlarge the square by 2: 1? Please discuss with each other at the same table.

(2) Report: The original side is 3 squares long, and the enlarged side is 6 squares long.

(3) Students draw a square on the square paper and enlarge it by 2: 1.

(4) Teachers sum up an important point in students' methods: first determine a fixed point and take it as it.

Determine the important points of the graphic position before drawing other parts.

(5) Teachers use multimedia courseware to show the process of drawing an enlarged square.

4. Go through the process of drawing rectangles and right triangles.

(1) Next, let's continue to enlarge rectangles and right triangles according to 2: 1. What do you think we need to know? Ask the students to answer.

(2) Let's enlarge rectangles and right triangles according to your method. Please draw them on paper.

(3) Students apply for pictures.

(4) Observing an enlarged right-angled triangle, two adjacent right-angled sides are magnified twice, so is his hypotenuse also magnified twice? How did you know? Report the measurement results.

5. doubt.

What are the similarities between the observation, enlargement and the original? What is the difference?

(1) What are the similarities between the enlarged image and the original image? What is the difference?

(2) Group cooperative learning and discussion to solve the problems raised by students.

(3) Select representatives to introduce their own methods and find the answers. The process of random demonstration and verification by teachers with multimedia courseware. (4) Students try to summarize their findings and show them through multimedia. A figure is enlarged in a certain proportion, and each side of it is also enlarged in the same proportion. )

(5) Multimedia presentation. When a figure is enlarged in a certain proportion, the figure becomes larger, but the shape remains the same.

(2) Perceptual restoration of graphics.

Teacher: We studied the drawing method of enlarging the figure according to a certain proportion, and some characteristics of enlarging the figure. How to draw a figure when it is reduced to a certain proportion?

1, indicating the requirement of reduction.

If the edges of three enlarged graphs are reduced by 1:3, what will happen to the graphs? Draw a picture.

2. Talk about the understanding of 1: 3.

3. Students draw pictures and check each other.

4. Choose the works of student representatives to show and talk about how to draw them. (multimedia completes the graphics drawn after being reduced in a certain proportion. )

5. Observe the original picture and the reduced picture. Students try to talk about their findings and try to summarize them.

Press 3: 1 to draw the following picture.

6. Summarize the survey results.

(1) student discussion.

What is the relationship between the obtained graph and the original graph after enlarging or reducing each side of the graph in the same proportion?

Students try to summarize the characteristics of enlarging or reducing graphics according to a certain proportion.

(2) Teachers use multimedia to show the zoom-in and zoom-out characteristics of graphics after students fully speak: the graphics obtained only change in size and shape.

Third, consolidate the application

Draw a picture,

Students give an enlarged or reduced ratio according to the teacher, and then draw a figure enlarged or reduced according to this ratio on the grid paper. After painting, students show their works and introduce the painting methods.

1, press 4: 1 to draw an enlarged picture below, and explain the reasons.

2. Press 1:2 to draw a miniature of the following figure.

3. Press 1:2 to draw a miniature of the following figure.

4. Which of the following pictures is obtained by enlarging Figure A by 2: 1?

5. Press 3: 1 to draw an enlarged view of the following figure.

It is mainly to evaluate students' mastery of the drawing method of enlarging and reducing graphics according to a certain proportion.

Fourth, class summary.

What did you learn from this lesson?

Conclusion: Students, today we learned the enlargement and reduction of graphics. In our daily life, there are many such phenomena. As long as you are conscientious in your life and apply what you have learned, you can create many new and interesting things to enrich and beautify our life.

Verb (abbreviation for verb) class assignment:

Textbook 1 and 2 questions

Enlarging and Reducing Graphics Teaching Plan (2) Teaching Objectives

1. Make students know the phenomenon of enlargement and reduction of graphics, and enlarge and reduce graphics according to a certain proportion in the form of grid paper to experience the similarity of graphics.

2. Through observation, understanding, hands-on operation and other mathematical activities, experience the process of graphic enlargement and reduction, and master the methods of graphic enlargement and reduction.

3. Feel the application and penetration of graphic enlargement and reduction in life? Change and invariability? Dialectical materialism viewpoint.

Emphasis and difficulty in teaching

Learn to focus on understanding the enlargement and reduction of graphics.

The difficulty in learning is to enlarge or reduce simple graphics in a certain proportion on grid paper.

teaching tool

Teaching aid preparation: PPT courseware teaching aid preparation: square paper

teaching process

First, create situations and introduce new lessons. (5 minutes)

Show me what it says. Zoom in and out of graphics? Small paper card.

Question: What is written on the paper card?

Because the words on the paper card are elementary five, students will be disappointed after they are eager to try, because they can't see clearly. )

Put the paper card on the booth, adjust the zoom button and gradually increase it.

Question: What is written on the paper card?

Why can't I see the words on the paper clearly before, but now I can see them clearly?

After the students answered, the teacher wrote on the blackboard.

Second, explore independently and understand the significance of graphic enlargement and reduction. (25 minutes)

1. Perceive the zoom-in and zoom-out phenomenon in life.

(1) The courseware shows the theme map on page 59 of the textbook.

(2) Question: Which of the above objects is a magnifying object? What is a shrinking object?

The teacher called the roll for the students to answer.

(3) The teacher will preset a picture in the computer, and pull the mouse to get the enlarged and reduced picture.

2. Explore the operation and understand the significance of graphic enlargement.

(1) Courseware display textbook Page 60 Example 4.

(2) Mass sending: What does it mean to enlarge 2∶ 1?

Name the students to answer.

(3) Students begin to draw on the square paper given by the teacher.

Teachers patrol and give individual guidance.

(4) Show students' works and exchange paintings.

(5) Guide observation and discovery.

Please look at the enlarged picture and the original picture. What did you find? (Guide students to observe from the inside angle, side length and perimeter)

② Deepening summary: the length of each side of each figure is doubled, the perimeter is doubled, and the internal angle remains unchanged. The figure is getting bigger, but the shape remains the same.

3. Cooperate to explore and understand the significance of graphic restoration.

(1) Question: If the enlarged square is reduced by1:3, the rectangle is reduced by1:4, and the triangle is reduced by1:2, what will happen to each figure? (guess)

(2) Students begin to draw a picture.

(3) communication. Courseware can be displayed and students can express their ideas. )

4. Summary and promotion: What are the similarities and differences between the enlarged or reduced graphics and the original graphics?

After the students answered, the teacher concluded that the length of each side of the figure was enlarged or reduced according to a certain proportion, and the size of the figure changed, but the shape remained unchanged.

learning plan

Students observe the teacher's operation, think about related problems and enter the new lesson.

1.( 1) Students observe the theme map and distinguish the enlargement and reduction of the object.

(2) It can be seen that reading a book with a magnifying glass, projecting a chart with a projector, the shadows reflected by the light are all magnifying objects, while taking pictures with a camera is narrowing objects.

(3) Students observe the teacher's operation and perceive the phenomenon of zooming in and out.

2.( 1) Students watch the courseware and get relevant information.

(2) Enlarging 2∶ 1 is to enlarge the length of each side of the graph to twice the original length.

(3) Students draw enlarged figures.

(4) Students show their works and exchange paintings.

(5) Students observe the relationship between the enlarged graph and the original graph.

(1) Students guess what happens when each number is reduced.

(2) Students draw reduced figures.

(3) Students exchange ideas.

4. Students summarize the changing characteristics of graphic enlargement and reduction.

Third, consolidate practice. (6 minutes)

1. After reading page 60 of the textbook? Do it. .

2. Complete questions 1 and 2 on page 63 of the textbook.

Fourth, class summary, expansion and extension. (4 minutes)

1. Tell me about the gains of this lesson.

2. Assign homework.

Summary after class

? Zoom in and out of graphics? It is a basic transformation of a graph, and it is a process in which the length of each side of the graph changes in the same proportion.

In teaching, it is of great practical value to pay attention to the connection between mathematics and life, make effective use of pictures in textbooks and let students understand this part of knowledge. At the same time, pay attention to guide students to understand the significance and characteristics of graphic enlargement and reduction through learning examples, so that students can realize that to enlarge or reduce a graphic according to a certain proportion, they only need to enlarge or reduce the length of each side of the graphic according to the same proportion; Only when the size and shape of the figure have changed can we truly understand the significance of the enlargement and reduction of the figure.

homework

1. Can you give examples of enlargement and reduction in life?

2.( 1) A square handkerchief with a side length of 15cm was enlarged according to the ratio of (4: 1), and the side length became 60cm.

(2) When a figure is enlarged at the ratio of 3: 1, the circumference of the figure will be expanded to (3) times and the area will be expanded to (9) times.

3. Reduce the graph (1) by 1: 2 and enlarge the graph (2) by 3: 1.

The area of a square is 100 square centimeter. How many square centimeters is the area of the graph enlarged by 10: 1?

Answer: 100? 102= 10000 (square centimeter)

A: The area of the enlarged drawing is 10000 square centimeters.

Write on the blackboard.

Magnification and reduction of graphics

The size has changed

Magnification and reduction of graphics

The shape has not changed.