Everything is fine. Elementary Mathematics from a High Viewpoint is published by Fudan University Press. The author Klein is a popular reading of basic mathematics based on his lectures for German middle school mathematics teachers and students at the University of G? ttingen for many years. This book reflects many of his views on mathematics and vividly shows people the legacy of first-class masters. After publication, it was translated into many languages, which is an immortal masterpiece of mathematics education, and its influence has never weakened. This book is divided into three volumes. Every volume has the benefits and knowledge of a volume. Book 1: Arithmetic, Algebra and Analysis; Volume II: Geometry; Volume III: Exact Mathematics and Approximate Mathematics.