One is the senior high school entrance examination, the other is the explanation, and the explanation can also be a whole book. Guidance is really a book that I have been using. The knowledge points are very detailed and close to the textbook. There are different solutions to common unexpected problems. It can reduce students' mistakes by picking out the ones that are easy to make mistakes. Also, the page numbers of the answers in the exercises are clearly marked, so there is no need to look for them page by page. The most important thing in mathematics is the answering steps, and the answering steps on demand are simple and comprehensive, so that teachers who change grades can't find anything wrong.