Forget about the calculator, this book will teach you how to do quick calculations in your head or with a pencil. To count faster, it is enough to think a little differently, its author Yngve Vogt, a Norwegian journalist for the scientific journal Apollon and a fan of mathematics, is sure. You will learn about simple and fun methods of quick counting, for which you only need to know basic arithmetic rules. The Trachtenberg method, the Chinese dash counting method and many other mathematical techniques will help you easily add and subtract, multiply and divide, take the square root and square large numbers.
