Compulsory one, compulsory two, elective compulsory one, compulsory two, compulsory three. The new mathematics textbook * * * has five books, the first compulsory, the second compulsory, the optional compulsory, the second compulsory and the third compulsory. The content of the first compulsory volume is the trigonometric function of the first compulsory volume and the fourth compulsory volume of the old textbook.