Numerical analysts and computer operators in all fields will welcome this publication in book form of Cecil Hastings' well-known approximations for digital computers, formerly issued in loose sheets and available only to a limited number of specialists. In a new method that combines judgment and intuition with mathematics, Mr. Hasting has evolved a set of approximations which far surpasses in simplicity earlier approximations developed by conventional methods. Part I of this book introduces the collection of useful and illustrative approximations, each of which is presented with a carefully drawn error curve in Part II. Originally published in 1955. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.