First, write. Arranging and combining requires strong logical thinking, and every situation needs to be considered. Because people's imagination has certain limitations, some situations may be left behind or cannot be counted. At this time, we will start writing, not only drawing, but also calculating and counting. Some simple statistics may make it very troublesome to calculate numbers. At this time, it is very important to list all possible situations and then calculate the total.

Secondly, there are ways to arrange and combine, such as "inserting spaces", which are used when the condition of "not adjacent" is required in the title, but it can also be every few non-adjacent, and another example is "binding method" (different places seem to be called differently). If two or more must be adjacent to each other, first tie them together as a row. After this row is over, tie the tied ones together. The method mainly depends on what the teacher teaches and summarizes himself, and what kind of questions and methods will get twice the result with half the effort.

Thirdly, clear your mind, whether it is permutation and combination or other math problems, you should clear your mind, and you can't just write down a condition or a situation, if it is useful. Every problem has the most direct way of thinking. For example, to find the volume of a cylinder, first find the radius, then the bottom area, and then the volume, and the arrangement and combination are the same. According to the characteristics of the problem, we should have our own way of thinking, whether to find the red ball or the white ball first. The thinking must be clear and must not be confused. If we are confused, it is easy for us to repeat or miss this situation.

Finally, don't be intimidated by the problem. In fact, some questions seem difficult at first glance, and many students are scared away. In fact, when you really do it, you will find that it is not difficult. In fact, you didn't have any ideas when you first examined the questions, and it doesn't matter. Try to examine the questions, draw pictures and find the rules again. Don't be intimidated. Math problems are like paper tigers. If you are not afraid of them, you can do them well.

Last but not least, don't make mistakes in the calculation. This calculation is quite error-prone. As long as the calculation is wrong, the previous work will be in vain and not worth it.

Finally, I wish my study progress, which is all my own experience. I hope to adopt.