One-week weather forecast data of Yantai

The purpose of teaching positive and negative numbers is to make students more familiar with the meaning of positive and negative numbers through examples in daily life and express things in daily life with positive and negative numbers. In the teaching process, we should carefully preset all aspects of teaching, provide students with more room for thinking, create a teaching situation close to students' cognitive rules and suitable for students' learning, and generate rich teaching resources for students' further study.

Positive numbers and negative numbers are two opposite definitions. In teaching, we should pay attention to the comparative study of these two concepts, so that students can better understand the meaning of positive and negative numbers. The relationship between positive and negative numbers and zero is a difficult point in teaching. Knowing the position of zero between positive and negative numbers is the key for students to correctly understand positive and negative numbers. I think we should pay attention to the following problems in the teaching process.

1. Situational content comes from real life, so the problem is discussed in depth.

"We often need to record data in our daily life and ask students to record the scores of the following two basketball games." Taking the real situation as the research material, different recording results are presented to reveal the students' original cognitive state. On this basis, research on new problems can not only make students fully feel the necessity of learning negative numbers, but also adjust teaching strategies according to the actual situation of students in this class. Make full preparations for effective teaching.

2. Collect effective materials in life and feel the meaning of positive and negative numbers and the relationship between them.

In teaching, I think we should pay attention to collecting effective materials in life. Listen to the weather forecast; Recognize it on the shopping receipt; Read according to the temperature in different places; Let's use real-life examples ... to make students realize that there are a lot of quantities with opposite meanings in life and the close relationship between mathematics and life. Obviously, positive numbers and negative numbers mean two opposite meanings. On the basis of students' perceptual knowledge, it is further abstracted that positive numbers can represent increasing, higher and positive, while negative numbers can represent decreasing, lower and reverse.

In this lesson, we should also make full use of the thermometer as a teaching aid to "write enough" and read the temperature from the thermometer; Trial writing temperature -5℃,-20℃; Set a specified temperature on the thermometer; Putting the thermometer horizontally and abstracting the number axis provides a very vivid basis for students to understand positive and negative numbers. When students study, there are concrete examples to rely on, and abstract concepts are easy to understand. Give full play to students' main role in activities without neglecting their main position, and ask many questions at key points: "Is the temperature in Shanghai (4 degrees above zero) the same as that in Beijing (4 degrees below zero)?" "Who is below -5℃ and -20℃?" "What is the difference between +5 degrees Celsius and-5 degrees Celsius?" ..... In the activity, students not only do it with their hands, but also think with their brains.

3. Dig deep into the mathematical ideas and methods reflected behind the knowledge, and correctly guide students to understand the objective world.

If you don't grasp negative numbers in life, it's easy to understand them one-sidedly, emphasizing only negative numbers and ignoring others. Objective things are interdependent. Without "positive", there is no "negative", and two aspects of things are indispensable. This is the basic viewpoint of dialectical method. What is to be conveyed to students through this teaching content is also such an idea, which should be raised from such a height. Therefore, in the whole class, the teacher closely focuses on two quantities with opposite meanings, so that students can contact, understand and learn. Finally, at the end of the class, students feel that "forward and backward can be represented by positive numbers and negative numbers respectively". The teacher's guidance is indispensable for the correct understanding and understanding of "increase and decrease can be expressed by positive numbers and negative numbers" and "quantities with opposite meanings can be expressed by positive numbers and negative numbers".

Classification is the basic way to know things. When people know things around them, they usually classify them according to standards, then discriminate them, and finally have a complete and clear understanding of things. Teachers also use classification methods when identifying positive numbers and negative numbers, focusing on the problem of 0. Students put 0 in an "unclear" position when classifying, and draw a conclusion through analysis and explanation: 0 is neither positive nor negative.

These designs have a broad perspective, not limited to a certain local space set by textbooks, but widely collect resources, fully develop and use them for us. So as to sweep away the boring classroom of concept teaching.