Thirteen Bao Shu books, eight in each pack, so the total * * * is 13*8= 104, each book is eight yuan, 104*25=2700 yuan.

Mathematical problems are generated by counting, calculating, measuring and observing the shape and motion of objects through abstract and logical reasoning. Mathematical problems can be roughly divided into fill-in-the-blank questions, true and false questions, multiple-choice questions, calculation questions, application questions, proof questions, drawing questions, thinking questions, reading questions, regular questions and problem solving. Skillful problem solving depends on the flexible use of the knowledge you usually study.