How to improve students' interest in learning mathematics and turn boring mathematics contents into intuitive images is a common concern of our mathematics teachers in teaching. In teaching, many students have many difficulties because of the boring content of mathematics, and even have fear and weariness of mathematics, and lose confidence in learning mathematics well. We use multimedia teaching technology to visually reproduce or simulate teaching information such as concepts and theorems in textbooks by means of words, images, animations, videos, etc., to stimulate students' senses, arouse students' interest, make students actively participate in teaching activities, and improve students' speed of learning knowledge and efficiency of absorbing knowledge. For example, in teaching this course, traditional teaching mainly focuses on lectures, which makes students feel boring, uninterested in learning and inefficient in teaching. Teachers' language expression is weak and it is difficult to achieve the ideal teaching effect. We can make FLASH animation to reproduce the situation, which not only enhances the interest of this class, but also helps students understand the law of rational number addition, and breaks through the teaching difficulties of this class well.