Some topics look big and complicated, but in fact there are not many key contents. Make a detailed analysis of the topic, get rid of the rough and the fine, get rid of the false and keep the true, and extract the main and key contents, so that the difficulty of the topic will be greatly reduced and the problem will be solved.

Finding the topic of mathematical laws will involve one or several variables. The so-called finding the law, in most cases, refers to the changing law of variables. Therefore, grasping the variables is equivalent to grasping the key to solving the problem.

Only by comparison can we tell. Through comparison, we can find the similarities and differences of things, and it is easier to find the changing law of things. To find a regular topic, we usually give a series of quantities in a certain order, which requires us to find a universal law according to these known quantities. The laws revealed often contain the serial numbers of things. Therefore, it is easier to find the mystery by comparing variables with serial numbers.

Some topics contain the circular law of things. If we find the circular law of things, other problems will be solved.

For example, in 2005, the math test in the senior high school entrance examination in Yulin City was: "Observe the arrangement rules of the following balls (in which ● is a solid ball ● is a hollow ball): ● ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ 9.