Find the location of the book according to the call number provided in the catalogue. Call number is a set of numbers consisting of letters and numbers, which generally includes the classification number of China Library Classification and the category number of books. The classification number represents the content of a book. For example, the classification number of the first book in the catalogue is I542.5, and Class I is literature, which means that this book is a literature book. The steps to determine the order of call numbers are as follows: first, compare the classification numbers; If the classification numbers are the same, compare the classification numbers. The books on the shelves of the library are arranged in the order of call numbers.