Show you the meaning of positive and negative numbers, and how to read and write.

1. Pay attention to the creation of situations and understand the meaning of negative numbers. Students already have some knowledge and experience about negative numbers before learning new knowledge, so I introduce students' familiar weather forecast into teaching and let them be small weather announcers. At first, some students read when reading the temperature in Harbin: Harbin is MINUS 27℃ to MINUS 19℃. Although the students' pronunciation. That's right, I asked. Is that what the weather announcer said on TV? At this time, the students immediately changed it to -27℃ in Harbin to-19℃, so as to have a preliminary understanding of the meaning of negative numbers and reflect on the teaching of negative numbers (original text). In the next teaching, the teacher asked the students to observe -3℃ and 3℃ and think about their meanings. It is concluded that 0℃ indicates the temperature at which fresh water begins to freeze. The temperature below 0℃ is called below zero. The temperature above 0℃ is called the temperature above zero. The above-zero temperature and below-zero temperature are represented by positive numbers and negative numbers respectively, which reveals that the specific meaning of positive numbers and negative numbers is to represent two quantities with opposite meanings.

2. Pay attention to the teaching of error-prone points. In previous teaching, students often make mistakes in the comparison of negative numbers because the teaching content of the number axis is not in place. In teaching, I grasp the knowledge point of number axis, and let students know that the number on the right of 0 is positive and the number on the left of 0 is negative. On the number axis, the order from left to right is from small to large. For example, the comparison between -2 and -4: Because -2 is close to 0, -2 is greater than -4.

Disadvantages:

1. In teaching, although students know that 0 is neither positive nor negative, because the plus sign can be omitted, some students appear in front of 0 and add the plus sign incorrectly.

2. For marking negative scores on the number axis, students are more likely to find positive scores on the number axis, but for negative scores, some students will make mistakes when marking them. The reason is that students still have blind spots in the order of negative numbers.

Re-instructional design:

In the future teaching, we should strengthen the comparison of negative numbers and the training of finding negative scores on the number axis, and strive to eliminate potential problems in the process of learning new knowledge.