This book focuses on "China students are obviously superior to the United States in the international comparative study of mathematical ability. Then, paradoxically, China's mathematics education is far less than that of American teachers. " The author explains this phenomenon at least at the primary school level. The data in this book show that when Mr. China started his teaching career, his understanding of mathematics was better than that of American teachers. They have a better understanding of the mathematics they teach than American teachers. Their understanding of the content of mathematics taught and the equally important understanding of the teaching methods of elementary mathematics have deepened in their career.

This book demonstrates the differences between Chinese and American teachers in mathematics teaching knowledge from some examples, and puts forward China's classroom understanding of mathematics and the role of teaching in students' success. This paper confirms some factors that support the growth of teachers' mathematical knowledge in China, and points out American teachers' mathematical understanding.

The following comes from exploring new knowledge: the relationship between perimeter and area?