Liu Hui believes that to solve practical problems by mathematical methods, we should use various mathematical methods as flexibly as possible on the basis of understanding the essence of mathematics. The so-called "easy to decide" should not be "single-minded" and inflexible. He used the fable of "A clever woman can't cook without rice" in Zhuangzi as a metaphor, saying, "Counting is still the blade. Easy to use, it moves on a skilled principle, so you can use God's love blade, which is fast and rare. " Therefore, he often puts forward several different solutions to a problem and different ways of understanding a solution, which greatly enriches the content of the nine chapters of arithmetic.