A GRAMMAR SCHOOL ALGEBRA BY FLETCHER DURELL, PH.D. MATHEMATICAL MASTER IN THE LAWRENCEVILLE SCHOOL AND EDWARD R. ROBBINS, A.B. MATHEMATICAL MASTER IN THE WILLIAM PENN CHARTER SCHOOL CHARLES E. MERRILL CO., PUBLISHERS, Durell & Robbins' Mathematical Series Durell & Robbins-Elementary Practical Arithmetic. 201 pages, 12mo, cloth, 35 cents: Durell & Robbins - Advanced Practical Arithmetic. 363 pages, 12mo, cloth, 65 cents Durell & Robbins-A Grammar School Al gebra. 287 pages, 12mo, half leather, 80 cents 374 pages, 12mo, half leather. Durell & Robbins-A School Algebra $1.00 Durell & Robbins-A School Algebra Com $1.12 plete. 483 pages, 12mo, half leather, Durell-Plane Geometry 341 pages, 12mo, half leather. Durell-Solid Geometry 213 pages, 12mo, half leather. Durell-Plane and Solid Geometry 514 pages, 12mo, half leather. 75 cents 75 cents $1.25 CHARLES E. MERRILL Co., PUBLISHERS 44-60 East Twenty-third Street, New York Copyright, 1897, by R. L. Myers & Co. PREFACE. THE principal object in writing this Grammar School Algebra has been to simplify principles and make them attractive, by showing more plainly, if possible, than has been done heretofore, the practical or common-sense reason for each step or process. Thus, at the outset it is shown that new symbols are introduced into algebra not arbitrarily, but for the sake of definite advantages in representing numbers. The fundamental laws of algebra governing the use of symbols derive their importance in like manner from the economies which they make possible in dealing with the symbols for numbers. Each successive process is taken up for the sake of the economy or new power which it gives as compared with previous processes. It is hoped that this treatment not only makes each principle clearer to the pupil, but also gives increased unity to the subject as a whole. It is also believed that this treatment of algebra is better adapted to the practical American spirit, and gives the study of the subject a larger educational value. While seeking to develop the theory of the subject in this manner, it has been deemed best to keep in close touch with the best current practice of teachers in other respects. For instance, the order of topics in text-books most used at present has been followed. Great care has been taken in the selection and gradation of a large number of examples. It is hoped that they have been so graded that any example may be considered the last of a series of progressive steps, provided the teacher wishes to limit the work at any particular point. Frequent reviews have been provided for, especially in the all-important subjects of Factoring, Fractions, Exponents, and Radicals. The present volume closes with the subject of Radicals, and is intended to contain only so much of the subject of algebra as pupils in Grammar Schools are likely to study. In other volumes all the topics required for admission to colleges and scientific schools will be covered. FLETCHER DURELL, EDWARD R. ROBBINS. LAWRENCEVILLE, N. J., |