30。 Math Journey to the West has 30 words per line. Mathematical Journey to the West tells the story that the cool monkey used mathematics to help Zhu Bajie and the Monkey King defeat monsters from all walks of life. There are 27 short stories in the book, each story is coherent, and each story involves a mathematical problem, which corresponds to the key and difficult points of classroom mathematics learning in the second and third grades of primary school, and emphasizes the mathematical thinking of multiple solutions to one problem.