Lecture activities are divided into two forms: pre-class lecture and after-class lecture. The above contents must be clearly stated in both pre-class lectures and after-class lectures. Before class, you should also talk about doubts, explain clearly the doubts you are not sure about in preparing lessons, and ask other teachers for advice. After-school lectures should also include. How are the students doing? Teaching effect evaluation based on. The following is my junior high school lecture "Number Axis" collected for you. Welcome to read!

Junior high school mathematics lecture notes: number axis

Teachers: Hello!

The class content I am talking about is the first class content of "Number Axis".

One: teaching material analysis:

This lesson is mainly based on students' study of the concept of rational numbers, indicating the temperature from a thermometer marked with scales.

Starting from this case, this paper introduces the drawing method of number axis and the method of expressing numbers with points on the number axis, and initially permeates the mathematical thought of combining numbers and shapes to students, so that students can understand the related problems of rational numbers with intuitive graphics. The number axis is not only an important tool for students to learn rational numbers such as reciprocal and absolute value, but also a necessary basic knowledge for them to learn inequality solving, function images and their properties in the future.

Second, the teaching objectives:

According to the requirements of the new curriculum standard and the cognitive level of grade seven students, I have formulated the teaching objectives of this lesson as follows:

1. Let the students understand the three elements of the number axis and draw them.

2. Can represent known rational numbers on the number axis, can tell the rational numbers represented by known points on the number axis, and understand that all rational numbers can be represented by points on the number axis.

3. Infiltrate the mathematical idea of combining numbers and shapes into students, let them know that mathematics comes from practice, and cultivate their interest in mathematics.

Third, teaching focuses on difficulties.

Correctly understanding the concept of number axis and the representation method of rational number on number axis is the teaching focus of this course, and establishing the corresponding relationship between rational number and points on number axis (combination of number and shape) is the teaching difficulty of this course.

Four: teaching material analysis:

(1) In terms of knowledge mastery, grade seven students have just learned the positive and negative numbers in rational numbers, and their understanding of the concept of positive and negative numbers is not necessarily profound. Many students forget knowledge easily, so we should speak it comprehensively and systematically.

(2) Knowledge barriers for students to learn this lesson. Students' understanding of the concept and three elements of number axis is not easy for students to understand, and it is easy to forget things in drawing, so teachers should make a simple and clear analysis in teaching.

(3) Due to the understanding ability, thinking characteristics and physiological characteristics of seventh-grade students, students are active, easily distracted and love to express their opinions, hoping to get praise from teachers. We should grasp this physiological and psychological characteristic of students in teaching, on the one hand, we should use intuitive and vivid images to arouse students' interest and keep their attention focused on the classroom all the time;

Because of the understanding ability and thinking characteristics of seventh-grade students, they often need to rely on the age characteristics of intuitive and concrete images, while seventh-grade students have just learned the positive and negative numbers in rational numbers. The understanding of the concept of positive and negative numbers is not necessarily deep, and many students easily forget their knowledge. In order to make the class lively, interesting and efficient, the whole class is specially observed.

Thinking and discussion run through the whole teaching process, adopting heuristic teaching method and teacher-student interaction teaching mode, paying attention to emotional communication between teachers and students, and teaching students a seminar-based learning method of "observing more, thinking more, making bold guesses and studying hard". In teaching, actively use blackboard writing and graphics in practice to provide more opportunities and space for students.

Make students get enough experience and development in the process of thinking, doing and speaking, so as to cultivate students' idea of combining numbers with shapes.

In order to give full play to students' subjectivity and teachers' leading and auxiliary roles, seven teaching links are designed in the teaching process:

(A), review the old knowledge, stimulate interest

(2) Draw a definition and reveal the connotation.

(C), hand-brain combination, in-depth understanding

(D), inspiration and induction, preliminary application

(5) Feedback and error correction, focusing on participation.

(6) Summarize and strengthen thinking.

(7) Assign homework and guide preview.

Five. Teaching plan design:

(a), review the old and learn new, stimulate interest:

First, review the question: rational numbers include those answered by students, and then let everyone discuss: can you find these examples of numbers expressed in scales? Students will give many examples, but because the thermometer is the closest to the number axis, and it is a graduated measuring tool that students are familiar with, I will use it to abstract and summarize it into a mathematical model of the number axis in teaching, so let students observe a group of thermometers and ask questions:

(1) 5 above zero? C is represented by 5.

(2) 15 below zero? C is represented by-15.

(3)0? C is represented by 0.

Then let's think about it: can we draw a scale on a straight line, mark the readings, and use the points on the straight line to represent positive numbers, negative numbers and 0? The answer is yes, which leads to the topic: number axis. Combined with examples, students can enter this class with a relaxed and happy mood, realize that mathematics comes from practice, and expect to learn new knowledge at the same time, so as to prepare mentally for the successful completion of teaching tasks.

(2) Draw a definition and reveal the connotation:

The teacher asked: What exactly is the number axis and how to draw it?

(1) Draw a straight line and take the origin (the explanation here is to take any point on the straight line as the origin, indicating 0, and the number axis is drawn horizontally, for the convenience of reading and drawing, and also for aesthetic feeling. )

(2) mark the positive direction (this shows that we are used to specifying the positive direction from the origin to the right on the number axis of the horizontal position.

For convenience, because we can only draw a part of a straight line, the arrow indicates the positive direction and the infinite extension. )

(3) Select unit length and scale number (here, choose any suitable length as the unit length, and take a point every other unit length from the origin to the right when scaling number, that is 1, 2,3? Negative numbers are the opposite. The length of unit length can be determined according to the actual situation, but the same unit length represents the same quantity. )

Because drawing several axes is the focus of this class, the teacher wrote these three steps on the blackboard to demonstrate to the students.

After drawing the number axis, the teacher leads the students to discuss: "How to describe the number axis in mathematical language" (inspiring the students through the teacher's kind language, thus cultivating the tacit understanding between teachers and students)

Through discussion, teachers and students come to the definition of number axis: the straight line defining origin, positive direction and unit length is called number axis.

At this point, we abstract a concrete thing "thermometer" into a mathematical concept "number axis", so that students can initially experience a cognitive process from practice to theory.

(3), hand and brain, in-depth understanding:

1, let the students discuss: which of the following figures are number axes, which are not, and why?

One,

b，

c，

d，

e，

f，

The three graphs A, B and C are three elements based on the number axis. D and F are mistakes that students may make. Give students enough time to observe and think, and then discuss them fully. Teachers participate in students' discussions in order to get in touch with students, understand students and pay attention to them.

2. In order to further strengthen the concept, please draw a number axis in the exercise book on the basis of a correct understanding of the number axis (please draw it on the blackboard).

Teachers patrol and give individual guidance when students draw several axes, paying attention to students' individual development. After drawing, the teacher gives comments, such as "very good", "very standard" and "the teacher believes in you and you can do it", etc., to motivate students and promote their development; It is emphasized that the origin, positive direction and unit length are the three elements of the number axis, which are indispensable when drawing the number axis.

I designed the above two exercises. One is to think with your head, judge right and wrong through analysis, and deepen your understanding of correct concepts. One is to deepen the understanding of concepts through hands-on operation.

(4), inspiration and induction, preliminary application:

With the number axis, all rational numbers can be represented on the number axis, so conversely, do the points on the number axis only represent rational numbers? As a question, I let students think and lay the foundation for the study of real numbers later, so I won't expand it here.

Example of arranging 23 pages of textbooks 1,

Let the students operate with the illustrations on the blackboard. The teacher asks:

1, mark the point on Line 2, and mark the number above the point.

Through students' practical operation, we can deepen our understanding of the number axis and further master the method of expressing numbers with points on the number axis.

At the same time, it can stimulate students' interest in learning and arouse their enthusiasm, so that students can truly become the main body of teaching.

Of course, this question can also be punctuated by several rational numbers for students, so that more students can show themselves and further let students feel that the known rational numbers can be expressed by points on the number axis, thus deepening their understanding of the idea of combining numbers with shapes.

(5), feedback correction, pay attention to participation:

In order to consolidate the teaching focus of this section, let students complete it independently:

1, exercise on page 23 of the textbook 1, 2

2. Three questions on page 23 of the textbook (show all students how to let a classmate write on the blackboard) further penetrate the idea of combining numbers with shapes for students to discuss:

3, the distance between point P on the number axis and point A representing rational number 3 is 2,

(1) Try to determine the rational number represented by point P;

(2) Move A to the right by 2 units to point B. What is the rational number represented by point B?

(3) Move 9 units to the left from point B to point C, then what is the rational number represented by point C?

Ask the students to get the results through group discussion. Through the above exercises, students can use what they have learned flexibly and form certain abilities.

(6), summarize and strengthen thinking:

According to the characteristics of students, teachers and students * * * together to sum up:

1, in order to consolidate the teaching of this lesson, the key question is: Do you know what the number axis is? Can you draw a number axis? In this lesson, you learned how to represent rational numbers.

2. Will there be two points on the number axis representing the same rational number and one point representing two different rational numbers?

Let the students firmly grasp that a rational number only corresponds to one point on the number axis, and can say the rational number represented by the known points on the number axis.

(7), homework, guidance preview:

For all students, the arrangement is as follows:

1, all students must make 25 pages of textbooks 1, 2, 3.

2. Finally, arrange a thinking question:

Similar to a thermometer, what is the size relationship between two rational numbers represented by two different points on the number axis?

(Guide students to form preview study habits)

Six. Blackboard design: (omitted)

In short, in the teaching process, I always pay attention to give full play to the students' main role, so that students can actively find conclusions through independent, exploratory and cooperative learning and realize the interaction between teachers and students. Through this teaching practice, good teaching results have been achieved. I realize that teachers should not only teach students knowledge, but also cultivate students' good mathematical literacy and study habits, so that students can learn to learn, so as to truly become a good teacher welcomed by students.

These are my thoughts on this course. Please criticize and correct the shortcomings. Thank you!

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