1, lead-in: Stimulate students' enthusiasm and initiative in learning rational number subtraction by creating problem situations.

2. Expand: First, guide students to explore laws through concrete examples and form rational number subtraction rules; Then guide students to learn examples and let them learn to operate skillfully; Then guide students to expand their applications and internalize and sublimate; Then review and summarize in class to deepen your impression.

3. End: Pass the standard test and give feedback, and finally arrange the operation and give feedback.

Teaching resources: the teaching content of rational number subtraction in the first chapter, the third section and the second section of the seventh grade mathematics textbook published by People's Education Press.

Teaching methods: Teachers use multimedia courseware, combine the content of this lesson with the actual situation of students, and guide students to discover the law of rational number subtraction by way of inspiration and guidance, and apply the law of subtraction to calculate rational number subtraction, and summarize the methods. Students can complete the learning tasks of this lesson through exercises and tests.

Teaching methods: learning before teaching, classroom training and cooperative inquiry.

Knowledge and skills: understand and master the subtraction rule of rational numbers; Can carry out the subtraction of rational numbers, can convert the subtraction of rational numbers into addition, and then write it in the form of the sum of omitted brackets and plus signs.

Process and method: let students infiltrate their thoughts by transforming subtraction into addition; By deducing the subtraction rule of rational numbers, students' logical thinking ability can be developed; Through the subtraction of rational numbers, students' operational ability can be cultivated.

Emotional attitude and values: By explaining the subtraction rule of rational numbers, the dialectical materialism thought of universal connection and mutual transformation between things is permeated.