101 Shortcuts in Math Anyone Can Do – Gordon Rockmaker (1965)
101 Short Cuts… teaches a streamlined left to right approach in as few steps as possible. Rockmaker wrote the book in a similar streamlined fashion. Most languages read left to right and for those native to that method, right to left in the minds eye goes against the grain to a very noticeable extent. All tricks in the book are, as the preface states, “authentic” in that they provide the answer quickly and easily in as few steps as possible thus eliminating the needless mechanics. You’re provided with tricks for addition, subtraction, multiplication (including squares), division, fractions, mixed numbers, AND percentages. In short, everything for pragmatic every day use.
Rockmaker cuts through the mental fog which most people interested in a book like this no doubt have (myself included of course). In school, most of us were taught in a way that was devised to show work on paper as a proof for the demonstration of understanding with the intention of applying a grade, the method of which is not generally friendly to the mind’s eye. The left to right approach in this book is far easier and much more pragmatic. I wish this book was part of my elementary school curriculum so I could’ve enjoyed these abilities much earlier in my life instead of decades later. This book is the recipe for a solid foundation in mental arithmetic, truly a game changer and I would go so far as to say life changing for someone as inept at mental arithmetic as I once was.