This book mainly tells the story of a clever mathematical monkey who happened to meet the Monkey King Pig Bajie and Friar Sand and went to the Western Heaven to learn Buddhist scriptures. They met many monsters along the way, all of whom were very strong.

The math monkey is responsible for calculating math problems, and the other three are responsible for killing goblins and pests for the people. They solved many mathematical problems along the way, including solving equations, periodic problems, profit and loss problem and many other interesting types of problems, but what I remember vividly is a percentage problem.