How about thinking education in the fourth grade spring class?
As long as you listen carefully, you will make progress. The teachers are familiar with the major competitions and the Olympic math problems. As long as you are willing to learn, you can learn from your teacher. The teacher's explanation is not deep, but the method is very practical. You can do the same thing by doing your homework when you come back. This effect is still very happy, because all the knowledge you have learned can be used.