No one can shake the position of this book in the popular science circle. Its content is all-encompassing, involving mathematics, physics, chemistry and biology. It is not only a simple knowledge introduction, but a high-level perspective, which can greatly improve children's interest in learning.

Direct calculus

Starting from common sense, this book directly defines the derivative of a function and proves its common properties, without using the concept of limit or infinitesimal. The definite integral is defined and the basic theorem of calculus is deduced. Strict and intuitive reasoning subverts the traditional view that calculus must be based on the concept of limit, solves some of the biggest difficulties in traditional calculus teaching, and draws a blueprint for establishing a new calculus system in high schools and universities.

How to Solve Problems: A New Mathematical Thinking Method

This book is a best-selling masterpiece of Paulia, an internationally renowned mathematician, who discusses the teaching methods of mathematics in middle schools. The book holds that the fundamental purpose of middle school mathematics education is to teach young people to think. He regards "problem solving" as a means and way to cultivate students' mathematical talent and teach them to think, and guides students to think according to the problems and suggestions in the table, explore the methods to solve problems, and then gradually master the general law of the problem solving process.