books
dead reckoning calculating without instruments
no author has gone as far as doerfler in covering methods of mental calculation beyond simple arithmetic . even if you have no interest in competing with computers youll learn a great deal about number theory and the art of efficient computer programming . martin gardner
paperback gulf publishing company 1993 isbn 0884150879
abridged n isbn 13 9780884150879 number of pages 182 publisher natl book network release date 62135769600000