I looked it up on the internet and said that abacus mental arithmetic is different from the thinking I learned in school in the future, and so is official document mathematics! In fact, as long as children are familiar with it, they will understand it thoroughly. I guess there should be no conflict in going to school in the future. Even if the thinking is different, it is two ways. Sometimes we do things in several ways! I'm afraid that children will learn half-baked, and that will be in trouble!