How to Calculate Quickly (The Art of Calculation)

Many useful procedures explained and taught: 2-column addition, left-to-right subtraction, direct multiplication by numbers greater than 12, mental division of large numbers, more. Also numerous helpful shortcuts. More than 8,000 problems, with solutions. This new Dover edition is an unabridged republication of the work first published under the title "The Art of Calculation", with corrections by the author. It is published through special arrangement with Duell, Sloan and Pearce, Inc.