I strongly recommend:
Language: primary school students understand all the textbooks (some teachers may not allow them to be sold, so it is recommended to buy them in grades 5 and 6 according to their children's situation), step by step, and encyclopedia of primary school students' composition (must buy).
Mathematics: All primary school textbooks are practiced, and oral arithmetic is practiced every day.
English: I know English like the back of my hand (don't forget the tape).