I made it in 2008, and the information in Chinese is very detailed. The quality of this math problem is really good. It will be divided into two sections, and the difficulty will gradually deepen. It is suggested that the first section should be written at the beginning of learning this chapter, and the second section can be written after the teacher finishes learning this chapter. This effect is very good, the key to mathematics is practice, but what is even more depressing is that the answer is very incomplete. You must remember to ask the teacher if you don't understand the question.