Mathematics is a subject with strong logical thinking, and the process of learning mathematics is a process of thinking training. It requires students to have certain abstract thinking ability, life knowledge and the ability to represent things. But in reality, some students are moderately and severely mentally retarded children. They are very short of this prerequisite for learning mathematics, and they encounter many obstacles when learning mathematics. Learning speed is slow and the effect is not good. Some students barely master the addition and subtraction within 10 when they graduate.

In order to promote the mathematics learning of students with mental retardation, it is necessary to make mathematics teaching as close as possible to students' real life. Only with the help of students' familiar life scenes and experiences can we better understand and master the most basic mathematical knowledge and skills, and can we use the learned mathematical knowledge to solve mathematical problems in real life.

I especially use McDonald's fast food restaurant to consolidate the skills of mentally retarded students in using RMB, because McDonald's is very attractive to children, and so are mentally retarded children. I take this opportunity to teach students to solve the application problem of "harmony" in different ways on the basis of their understanding of the monetary value, conversion, simple addition, subtraction, multiplication and division and application problem solving of McDonald's fast food restaurants. I first went to McDonald's restaurant to collect several boxes of food and distributed them to students in class, so that students could figure out how much they needed according to the price tag above and tell them how to do it. Students have fun in class, learn easily and master knowledge more firmly.