And what is the role of primary school students in learning mathematics? The problem of sum and difference times is an important knowledge point of Olympic mathematics in primary schools, and it is also a hot test point in various cup competitions. But it is also something that children need to know in primary school. According to a teacher's experience, it is of great help to middle school study in the future. Moreover, these knowledge, which is more difficult than the primary school textbooks, can make children fully use their brains, thus training their mathematical thinking ability, and at the same time, their basic computing ability has also improved a lot.