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 you'll learn a great deal about number theory and the art of efficient computer programming.
Excellent. Some of the tricks I knew and already used, but the algorithms for roots and logarithms are great, as well as the many tricks for trigonometrical functions. Much better than the truncated power series I've used in the past
I picked up this particular book at my local library because I found the idea of making calculations without a calculator useful as it wasn't really taught when I went to school. Unfortunately, I found the methods in this book to be just as bad as the Common Core method with the grouping and overall confusing layout that lacked clear explanations. I recommend this book to NO ONE!