Idiot's guides

Includes index

High-speed operations. Multiplication ; Addition ; Subtraction ; Division ; Checking your answers with digit sums -- High-speed math applications. Fractions ; Decimals ; Percentages ; Divisibility ; Squared numbers ; Cubed numbers ; Numbers to the fourth and fifth powers ; Square and cube roots -- Practice problems -- Answer key

"Simple methods for doing math quickly in your head; Shortcuts and tricks for on-paper calculations; Helpful insights to improve your understanding"--Page 1 of cover