READ SYSTEM OF COMMERCIAL TEXTS EDITED BY HARLAN EUGENE READ ADMIRE BAYS. DEFFENDALL DEFFENDALL GOFF. LISTER MEYER READ READ AND HARVEY PROGRESSIVE TYPEWRITING BUSINESS LAW ACTUAL BUSINESS ENGLISH EXERCISE BOOK (TO ACCOMPANY AC- ACTUAL BUSINESS CORRESPONDENCE VOCABULARY - BUILDING BUSINESS RAPID CALCULATION BOOKKEEPING AND ACCOUNTING These nine new books, each independent of the others and covering its own subject exclusively, are built to fit one another. Together they cover the fundamentals of commercial education, except shorthand, without omissions, unnecessary duplications, or inconsistencies. All subject matter not in common use in the business world is omitted. OF BUSINESS ARITHMETIC BY THOMAS T. GOFF HEAD OF THE DEPARTMENT OF COMMERCIAL ARITHMETIC New York THE MACMILLAN COMPANY All rights reserved EDITOR'S INTRODUCTION Hundreds, perhaps thousands, of the teachers whom the author of this book has trained in his classes will find in it expressions and teaching processes they first heard in his class-room. In his Self-proving Business Arithmetic Mr. Goff presents as the basis for the students' work the plan of requiring the student to prove the correctness of his own work before turning it in. Every problem in arithmetic can be worked two ways, or more. You may add up or down. You may figure interest by calculating first at six per cent or you may use first the given rate. You may compute a series of discounts one at a time or by first reducing the value of the series to a single result. When you multiply a number by a fraction you may divide first or multiply first. In all these cases the results must be the same. The idea is simple. Every teacher of arithmetic knows it. But as far as I know, Mr. Goff in this book has first applied this tremendous time-saving and thought-compelling plan to all the work given in a text-book. The importance of the discovery is comparable to that of doubleentry in bookkeeping. As the trial balance proves the accuracy of debits and credits, the self-proving method proves the correctness of calculations. 573602 |