Brain Games: The Greatest Puzzle Book EverPaperback, 1 August 2012

A series of simple steps that anyone can use to add, divide, subtract, and multiply sums that seem impossiblewith no pencil, paper, or calculatorMany peopletend to avoid situations wherethey must reach for the calculator or, even worse, work things out in their head, but the system outlinedhere willchange that. This wonderful and fun book will teach readershow to perform a range of mathematical tasks, from simple addition to complex equations, with ease, ensuring that the frustration numbers cause is banished forever. And, of course, it will nourish the showoff in everyone."