Reflection on the classification of angles

Part 1: Reflection on the classification of angles

The Classification of Corners is a simple basis for students to have learned about corners and have a metric angle. Right angles, acute angles, and obtuse angles are the corners that students often see. The definitions of them should be correctly described by the students after comparison, imagination, and reasoning. On the basis of the students' understanding of the diagonal, they present patterns such as right angle, acute angle, obtuse angle, flat angle and circumference angle. Under the guidance of the classification idea, three special angles appear at the same time, forming a module of problems, providing time and space for students' thinking.
1. Students are good at discovering teaching problems from daily life and activating life experiences.
Let students fully experience mathematics from life. Our daily life is a big classroom for learning mathematics. It is a vast world for exploring problems. Applying the knowledge we have learned to life practice is the ultimate goal of mathematics learning. Many mathematical laws and mathematical thought methods can find their prototypes in life. Students are good at capturing life materials. Teachers try to provide learning space so that students can get the initiative to explore mathematics from the perspective of life experience and existing knowledge. Through "finding the corners of objects commonly found in life", students feel that mathematics is closely related to life, which enhances students' understanding of the value and role of mathematics and stimulates students' enthusiasm for learning mathematics.
2. Guide students to practice and explore independently to promote mathematics thinking.
Focus on guiding students to practice, understand knowledge and develop thinking in operation. I changed the situation in which the teacher dominated the classroom, boldly let go, and changed the past to see the teacher's demonstration as a student's own initiative, mobilizing the initiative of the students. This lesson is designed to "find", "speak", and "do" to help students understand the angles and perception angles in mathematics activities, so that the interest in learning is relatively strong, and the students' observation ability and operation ability are effectively cultivated. Ability to express and analyze and generalize. Ask the students to use the activity angle to turn out an acute angle that they like, and talk about what kind of corner is called an acute angle. Then turn out a right angle, and also ask for a quantity, and then draw a conclusion. When teaching obtuse, you also have to go through this process. When teaching the corner, I asked the students to carefully observe the rotating side of the tool, and the wooden strip was rotated around its end, which gave the angle of 360 degrees.
In the teaching part of the classification part of exploring the new knowledge, because of different criteria, there must be different classification results. In addition, because the middle-aged students are weak in analysis, induction, and generalization, it is inevitable that there will be loopholes in thinking and logic errors. This requires teachers to provide students with practical operation time, opportunities for cooperative learning, and a platform for mutual communication. Therefore, the teacher organized the students to work together in groups, and then reported the exchanges in groups. In this way, students can understand mathematics, solve problems, discover loopholes in thinking in group communication, and constantly improve their knowledge systems.
Inadequacies, in the teaching of the week, did not guide students to use their own words to describe the formation process of the Zhou angle, and how this 360 degree is drawn, did not discuss with the students. If you can use the multimedia to slowly demonstrate, let the students observe the range it has turned. This can be done: first go to the right angle, ask: What angle is it now, how many degrees? Continue to the position of the boxer, ask: What angle is it now, how many degrees? From this, the angle of the circumference is 360 degrees, and the angle of the week is 2 flat angles and 4 right angles.

Part 2: Reflection on the classification of angles

Mathematics comes from life. Our daily life is a big classroom for learning mathematics. It is a vast world for exploring problems. Applying the knowledge we have learned to life practice is the ultimate goal of mathematics learning.
Regarding the "corner", the students have had initial contact in the second grade, but most of them are intuitive descriptions. Students touch a lot of different angles in their daily life, but the knowledge of the classification of common angles is very close in life. Less, it seems more abstract. Although there is a certain development in the abstract thinking of the students of the fourth grade, the image-based thinking is still dominant, and the ability to analyze, synthesize, generalize, and generalize is weak, and needs to be further cultivated.
I started from the reality of life, let the students capture the life materials themselves, and then proceed from the life experience and the existing knowledge background. With regard to the classification of the corners, I let the students actively participate in, operate, communicate, brain, and explore. Establish concepts, understand concepts, and apply concepts in learning. Give them the pleasure of actively exploring mathematics.
In the classification teaching of angles, the flat angle and the circumferential angle are the key points and the difficulties. Students tend to confuse them with rays and lines. Therefore, in teaching, I firmly grasp the characteristics of the corner to explain the particularity of the flat angle and the angle of the week. And pay attention to the contrast between the contrast of rays and lines. In the painting method of the corner, I took the hand to let the students paint, and guided the students to experience and summarize the painting in the process of painting. Because of the experience of the protractor angle, most students can meet the target requirements.

Part 3: Reflection on the classification of angles

"Classification of Corners" is the second unit of the seventh volume of the teaching materials. The teaching of "Classification of Corners" is mainly to let students learn to distinguish between right angles, acute angles, obtuse angles, flat angles and circumferential angles according to the degree of the angle, and know the right angle. The relationship between the flat angle and the angle of the week, to cultivate students' practical operation and observation and comparison ability. Under the guidance of the classification idea, three special angles appear at the same time, forming a module of problems, providing time and space for students' thinking. "Classification of Corners" and "Drawing of Corners" are two contents of the same class. In order to make students better mastered, I divided two classes.
It is the ultimate goal of mathematics learning to let students fully experience mathematics from life and apply it to life practice. Many mathematical laws and mathematical thought methods can find their prototypes in life. Students are good at capturing life materials. Teachers try to provide learning space so that students can get the initiative to explore mathematics from the perspective of life experience and existing knowledge. Through "finding the corners of objects commonly found in life", students feel that mathematics is closely related to life, which enhances students' understanding of the value and role of mathematics and stimulates students' enthusiasm for learning mathematics.
Secondly, it focuses on guiding students to practice, understanding knowledge and developing thinking in operation. I changed the situation in which the teacher dominated the classroom, boldly let go, and changed the past to see the teacher's demonstration as a student's own initiative, mobilizing the initiative of the students. This lesson is designed to "find", "speak", and "do" to help students understand the angles and perception angles in mathematics activities, so that the interest in learning is relatively strong, and the students' observation ability and operation ability are effectively cultivated. Ability to express and analyze and generalize. Ask the students to use the activity angle to turn out an acute angle that they like, and talk about what kind of corner is called an acute angle. Then turn out a right angle, and also ask for a quantity, and then draw a conclusion. When teaching obtuse, you also have to go through this process. When teaching the corner, I asked the students to carefully observe the rotating side of the tool, and the wooden strip was rotated around its end, which gave the angle of 360 degrees.
In the teaching of the classification part of the new knowledge, there are bound to be different classification results according to different standards. In addition, because the middle-aged students are weak in analysis, induction, and generalization, it is inevitable that there will be loopholes in thinking and logic errors. This requires teachers to provide students with practical operation time, opportunities for cooperative learning, and a platform for mutual communication. Therefore, the teacher organized the students to work together in groups, and then reported the exchanges in groups. In this way, students can understand mathematics, solve problems, discover loopholes in thinking in group communication, and constantly improve their knowledge systems.

Part 4: Reflection on the classification of angles

The fourth grade mathematics book "The Classification of Corners" Teaching Reflections on "Angle", the students have had initial contact in the second grade, but most of them are intuitive descriptions. Now it is the characteristics of the graphics that are properly abstracted on the basis of the second grade. , the concept of the system learning angle, the measure of the angle, the classification of the angle and the drawing of the angle, and so on. The classification of the angle is based on the fact that the student has initially recognized the angle and will use the angle angle of the protractor to further understand the flat angle and the circumferential angle. According to the degree of the angle, the right angle, the flat angle, the acute angle, the obtuse angle and the circumferential angle are distinguished. Students touch a lot of different angles in their daily lives, but the knowledge of the classification of common angles is rarely touched in life, and it is more abstract.
Although there is a certain development in the abstract thinking of the students of the fourth grade, the image-based thinking is still dominant, and the ability to analyze, synthesize, generalize, and generalize is weak, and needs to be further cultivated. Mathematics comes from life. Our daily life is a big classroom for learning mathematics. It is a vast world for exploring problems. Applying the knowledge we have learned to life practice is the ultimate goal of mathematics learning. Therefore, I proceed from the reality of life, let students capture the material of their own life, and then proceed from the background of life experience and existing knowledge, so that they can actively explore the joy of mathematics happiness.
According to the knowledge of the students' existing watches, I first let the students watch the clock and say that when the hour and minute hands are at a 90 degree angle? When is the time, the hour and minute hands are at an angle of 180 degrees? Students quickly get 90 degrees at 3 or 9 o'clock and 180 degrees at 6 o'clock. Then I asked the students to say 2 o'clock, how many degrees of the hour and minute hands? At that time, a few students spoke out and spoke different ideas. One classmate said that 3 o'clock, the hour and minute hands are 90 degrees, and at 3 o'clock, the minute hand goes 3 squares, that is, 3 is 90 degrees, then 1 is 30 degrees, so 2 o'clock, hour and minute hands In a 60-degree angle; another student said that the hour hand went from 12 o'clock to 12 o'clock, and walked 360 degrees, and there were 12 grids on the clock face, so each cell was 30 degrees, so when it was 2 o'clock, the hour hand And the minute hand at a 60 degree angle. Next, I asked how many degrees of angle do you get at 9:30? As a result, many students were fooled. They thought that they formed a right angle. Finally, only one classmate in the class answered correctly. His summary made many students realize that the hour and minute hands were moving, but the hour hand went slowly, and the minute hand went. It’s fast. In the inquiry activities, the students formed a preliminary information gathering ability, analytical ability, and experienced the pleasure of exploring the results themselves, which can better stimulate students' desire to explore the world.
At the end of the lesson, I worked with the students to find the corners of life and effectively extended the knowledge of the textbooks. In short, with regard to the classification of angles, I allow students to establish concepts, understand concepts, and apply concepts in the active learning, operation, communication, brainstorming, and dynamic inquiry learning. Practice has proved that the change of students' learning style can stimulate students' interest in learning, let the classroom rejuvenate the vitality of teachers and students, and make the classroom more exciting.

Chapter 5: Reflection on the Classification of Corners

Today's content is relatively small. After the lecture, I asked the students to read the book and then asked the students if they had any problems or what they didn't understand. The students thought for a while, and one student suggested: Is there a corner larger than the angle of the week? I know of course there is, but what method is used to let the students understand that I haven't figured it out yet, and I have given the question to the students: Do you say that there is a bigger angle than the angle of the week? Some students said: The angle of the week is the biggest, there is no greater angle than the angle of the week. After thinking for a while, some students said: It is bigger than the angle of the week, and it will take a few more weeks. Another student said: No, if it is more than a week, it must start from 0.
When I heard this, I thought about the diving and gymnastics competitions in the Olympics. I told the students that we had seen the diving competition in the Olympic Games in Beijing last month. During the diving competition, the narrator said that an athlete in the process of diving in the air 720 degrees in the air is greater than the 360 ​​degree angle? In actual life, there is such a corner that is larger than the angle of the week. The student immediately thought of it: there are also such angles greater than 360 degrees in gymnastics.
I don't know if the example I gave is appropriate. Please give me a mention after reading it, but I have two feelings. 1 is to use the things around the students to illustrate, the students are easy to understand, and they can make students feel better. The connection between mathematics and life; 2 is that students can give us some surprises as long as they believe in students and give students time and opportunities.