I. teaching material analysis
The area of combined graphics is the first lesson of Unit 5, Grade 5, Beijing Normal University Edition. Students learned the area calculation of rectangles and squares in the third grade, and the area calculation of parallelograms, triangles and trapezoid in the second unit of this book. The area calculation of combined graphics in this lesson is the development of these two aspects of knowledge, and it is also a problem that often needs to be solved in daily life. On this basis, learning combined graphics can not only consolidate the basic graphics that have been learned, but also synthesize the knowledge that has been learned and improve students' comprehensive ability. The content of the textbook highlights two parts, one is to feel the necessity of calculating the area of combined graphics, and the other is to emphasize students' independent exploration and learning according to the characteristics of combined graphics.
Second, the teaching objectives
1, knowledge and skills
(1) In the activities of independent exploration, learn about various methods for calculating composite graphs.
(2) According to the conditions of various combined graphs, the calculation method can be effectively selected and the correct solution can be given.
(3) Be able to use what you have learned to solve practical problems about combined graphic areas in your life.
2. Process and method
Let students cooperate and communicate on the basis of independent exploration, so as to sum up the calculation method of combined graphic area.
3. Emotional attitudes and values
(1) With concrete examples, I feel the necessity of calculating the combined graphic area, which has a positive emotion for mathematics learning.
(2) Mathematical ideas and methods of infiltration transformation.
Third, the importance and difficulty of teaching
1, teaching focus: Students can master the calculation method of cutting and filling method to calculate the area of combined graphics through their own hands-on operation.
2. Difficulties in teaching: Understand various calculation methods for calculating the area of combined graphics, and choose the most appropriate method to calculate the area of combined graphics according to the relationship between graphics and certain hidden conditions.
Fourthly, the analysis of learning situation.
The teaching object of this class is the fifth grade students. Through the previous study, students have a certain foundation for intuitive perception and understanding of plane graphics, and also mastered some methods to solve basic graphics problems. As a fifth-grade student, we should further improve the comprehensive application ability of knowledge and explore and master the thinking strategy of solving problems in our study.
Verb (abbreviation for verb) Speaking and teaching methods
Situation introduction
Create situations to guide thinking and let students study happily. Therefore, I consciously use intuition in teaching and try to create situations, which is of great benefit to improving teaching effect. "Interesting puzzle", through "spelling" and "speaking", the meaning of combined graphics is deduced.
Visual demonstration method
The intuitive image of students' interest in learning is intuitive and easy to remember, and happiness stimulates learning. Using multimedia courseware and learning tools, students can experience the process of knowledge acquisition through hands-on practice, operation and personal experience.
Guided teaching
In teaching, teachers should stimulate students' learning motivation and arouse students' strong interest in learning. Teachers should give careful guidance, students should learn skillfully, teaching and learning should be discussed, and support and release should be combined. When students work together in groups to explore solutions to problems, when students come up with different methods, guide them to compare and summarize the similarities and differences of the methods themselves, and at the same time know how to choose the appropriate method to solve problems according to conditions.
Six, said the learning method
1, independent observation and thinking
Students are the main body of learning. Only when students really take the initiative and actively participate in learning can the learning effect of students be improved most effectively. Guiding students to observe the characteristics of combined graphics, thinking about solutions and gradually building their own knowledge system is also conducive to the cooperative learning of the following groups, better listening to other people's different opinions and further improving their knowledge system.
2. Group cooperative learning
Group cooperative learning can help students get more methods and find suitable and effective solutions to problems through cooperation with others in a limited time. This lesson allows students to further broaden their thinking space and improve their learning ability through group cooperative learning on the premise of independent observation and thinking.
3. Learning summary.
In the past, teachers always helped students sum up what they had learned. Now, students can sum up what they have learned by themselves, which can help them further improve their study of new knowledge.
Students prepare: Students prepare rectangular, square, parallelogram, triangle and trapezoid pictures. Every graph has an edge with the same length. )
Teaching process:
First, understand the combined graphics in the jigsaw puzzle.
1, spell it.
Spell this activity and arrange for students to finish it at home before class. The teacher provides the students with difficult problems.
Puzzle requirements: (1) spell a new figure that I haven't learned before.
(2) Spell with three basic figures.
(3) Draw only the new graphics you pieced together on the paper.
Step 2 guess
(1) Swap works sit at the same table and guess each other. What simple figures does this figure consist of? Then find a group of wrong guesses for feedback.
(Design intention: According to students' existing knowledge and life experience, let students prepare puzzles and trapezoid games before class, and let students guess. Students may guess right or wrong. The purpose is to make students understand that combined graphics are composed of many kinds of plane graphics, and there are many different combination methods. This not only makes students full of enthusiasm and interest, but also increases the mystery and challenge. At the same time, make students have perceptual knowledge of combined graphics in their minds. )
(2) Teacher: How did you get these figures?
Teacher's summary: Although the shapes of the spelled figures are different, they are all spelled out by several simple figures, so we also call these figures combined figures.
Revealing the theme: Today, we will learn the knowledge of combined graphics. (Teacher writes on the blackboard: combined graphics)
Second, look for calculation methods in exploration activities.
1 Independent exploration, cooperation and exchange, and sharing methods.
The teacher shows two figures. Let the students guess and draw a picture. What are the basic figures of these two figures? (Title 1 on page 76 of this book)
Students first try to divide the combined graphics into basic graphics by themselves, then communicate with the partners in the group and then communicate with the whole class.
2, combined with the method, calculate the regional countries, exchange and compare.
On the basis of students' exchange of various segmentation methods, the conditions of combined graphics are given, and students can calculate the area of combined graphics.
In this part of students' activities, some students may not find the area of combined graphics according to their own segmentation methods, and some students who are segmented are more complicated and troublesome than complicated calculations. In view of these possible situations, guide students to discuss comparative calculation methods in classroom communication.
In the process of comparison, students feel that the simpler the segmentation method is when solving problems, the simpler the problem-solving method will be, and the relationship between the segmentation graph and the given conditions should be considered. Some segmented graphics are difficult to find relevant conditions, and such a segmentation method is a failure. If students have the method of "compiling" when exploring, then teachers can use this as a carrier to discuss with students. If students don't have such exploration methods, teachers can also give appropriate guidance before discussion. The focus of the discussion is why do you want to add a piece? What is the calculation method after adding a piece? Let every student understand this calculation method.
(Design intention: I rearranged the teaching materials in this part. In the teaching of exploring the area calculation method of combined graphics, I didn't use the situation given in the book, but on the basis of students' understanding of combined graphics through hands-on operation in the past, as an introduction, after students fully communicate and experience, I gave the known conditions of combined graphics, so that students could seek the calculation method at one breath. This makes students' learning more challenging, and students' learning emotion has been well developed. )
Third, practical application, expansion and perfection.
1, page 75 of the book.
2. Question 2. In the book, carefully observe the pictures and choose useful data. How do you want to calculate? Communicate your methods in groups. Report by name. For different algorithms, teachers and students analyze together and improve simpler methods to give guidance.
3. In the third question in the book, students think about calculation independently, and then talk about their own ideas.
(Design Intention: The 75-page situation, questions 2 and 3 in the book are all applications of combined graphic area in life, which can make students realize the need to solve practical problems. Through the above practice of solving practical problems, students can feel that mathematics is around us and there is mathematics everywhere in their lives. )
Fourth, sum up the gains and reflect on improvement.
Teacher: What have you gained from learning this lesson?
Guide the students to talk about what they have learned. How did you learn it? What other questions are there? It is very important for students to think independently and learn from each other, that is, different learning methods such as independent exploration, cooperation and exchange can also gain something.
(Design intention: The purpose of the summary is to let students review the content of this lesson. Because it is a senior, the teacher should guide the students to improve their summary. In terms of knowledge, there should be gains in mathematical methods and ideas. )
Fifth, homework.
1, page 76 in the book. Try it.
2. 76 pages of practical activities in the book.
(Design intent: There are two layered operations. The first assignment is a basic problem, and every student should finish it carefully and independently. The second assignment is practical activity. This assignment gives students more room for development. Students all know the flag of China team, but if we want to calculate its area, we may not know much about its data. Students who want to know the accurate data can help each other through their peers or ask the team counselor. Some students may ask their parents, and some students may know it through the internet. This kind of homework can effectively cultivate students' ability to solve practical problems. )