If you have the ability, the Olympic math book is the most effective. However, if some people can't understand the difficult questions, it is ok to understand the content of the textbook first. At least, they can get all the basic questions. After understanding all the problems in the math book, they can buy a slightly more difficult exercise book to do. If they can do it, learning olympiad is the most effective. It is also good to find more games to train logical thinking. It is also suggested to learn chess and play Jiugongge, which is good for future mathematics.