Why is 2 times 3 equal to 3 times 2? One may think this is an axiom, but it has a proof, and a beautiful one at that. Elementary mathematics is as deep and as beautiful as higher mathematics. It includes some of the most important mathematical discoveries ever, for example the concept of the number, and the place-value method of representing numbers. We are so accustomed to this method, that we forget how clever and beautiful it is — resulting in its incredible efficacy.All this was a surprise for the author, a university professor of mathematics, when he went to teach in elementary school. He realized that good teaching of elementary mathematics requires understanding its fine points and conveying their beauty to the students. Sensing the beauty and understanding go hand in hand.The book outlines the material from kindergarten to grade 6 (with an excursion into algebra as well). It also discusses teaching principles, and their close relatives — thinking principles. Teachers and parents who imbue these principles are likely to convey the love of mathematics to the child.