If you really want high returns, it must be one-on-one. If the family economy is not very rich, I suggest you give primary school counseling (I don't know how tall your child is). In fact, primary school mathematics is not difficult, and even parents can teach it. The key point still depends on whether the child is interested. Personally, I think that in fact, small classes are enough for primary schools, but if there are not many people, it will be the same as schools. If you get this score in junior high school, it will be very dangerous. It is better to fight one-on-one