Interest is the best teacher. Interest plays a great role in promoting students' learning. With interest, the efficiency of learning will be significantly improved. "Mathematics Curriculum Standard" points out that mathematics learning must start from students' living situations and things of interest, and provide them with opportunities to participate in learning activities, so that they can feel that mathematics is around and have a sense of intimacy with mathematics. Students in the lower grades of primary school have a short time to concentrate. If the whole class is explained by a single teacher, it will be boring and it will be difficult to attract students' attention. Instructing students to operate properly in class can stimulate students' interest in learning, enliven the classroom atmosphere, deepen their understanding and mastery of what they have learned and strengthen their memory.