This book is the result of a unique experience: a research mathematician teaching in an elementary school. It summarizes this experience and quickly became a bestseller in Israel. It tells about a fascinating discovery made by the author ?that elementary mathematics has a lot of depth and beauty, and that the secret to its teaching is to understand its deep points. The first part of the book discusses the nature of mathematic and its beauty. The second part tells about the teaching principles the author distilled from his experience. The third part is an excursion through the arithmetic studied in elementary school, accompanied by personal stories, historical anecdotes and teaching suggestions. The appendix relates the fascinating story of modern day politics of mathematical education.This is a unique guide for parents and teachers, describing vividly and informally the principles of teaching mathematics in elementary school. It is written from the perspective of a mathematician, and goes into the delicate mathematical points that are the secrets to teaching well.