Yale College, Nov. 27, 1799. I HAVE read DABOLL'S SCHOOLMASTER'S ASSISTANT. The arrangement of the different branches of Arithmetic is judicious and perspicuous. The author has well explained Decimal Arithmetic, and has applied it in a plain and elegant manner in the solution of various questions, and especially to those relative to the Federal Computation of money. I think it will be a very useful book to Schoolmasters and their pupils. JOSIAH MEIGS, Professor of Mathematics and Natural Philosophy. [Now Surveyor-General of the United States.] I HAVE given some attention to the work above mentioned, and concur with Mr. Professor Meigs in his opinion of its inerit. NOAH WEBSTER. New-Haven Dec. 12, 1799. Rhode Island College, Nov. 30, 1799. I have run through Mr. DaBoll's SchoolMaster's Assistant, and have formed of it a very favourable opinion. According to its original design, I think it well " calculated to furnish Schools in general with a methodical, easy, and comprehensive System of Practical Arithmetic.” I therefore hope it may find a generous patronage, and have an zxtensive spread. ASA MESSER, Professor of the Learned Languages, and teacher of Mathematics. [Now President of that Institution.) Plainfield Academy, April 20, 1802 I make use of Dapoll's SchoolMASTER's Assistant in teaching common Arithmetic, and think it the best cal culated for that purpose of any which has fallen within my observation. JOIIN ADAMS, Rector of Plainfield Acadeńy. [Now Principal of Philips' Academy, Andover, Masu.] Billerica Academy, (Mass.) Dec. 10, 1807. Having examined Mr. Davoll's System of Arithmetic, I am pleased with the judgment displayed in liis method, and the perspicuity of his explanations, and thinking it as easy and comprehensive a system as any with which I am &cutainted, can cheerfully recommend it to the patronage pi Instructers. SAMUEL WHITING, Teacher of Mathematics. From Mr. Kennedy, Teacher of Mathematics. I BECAME acquainted with DABOLL's SchoolMASTER'S As vistant, in the year 1802, and on examining it attentively, gave it my decisive preference to any other system extant, and immediately adopted it for the pupils under my charge; and since that time have used it exclusively in elementary tuition, to the great advantage and improvement of the student, as well as the ease and assistance or the preceptor. I also deem it equally well calculated for the benefit of individuals in private instruction ; and think it my duty to give the labour and ingenuity of the author the tribute of my hearty approval and recommendation. :3 ROGER KENNEDY New-York, March 20. 1811. PREFACE. sli The design of this work is to furnish the schools of the Laited States with a methodical and comprehensive system 01 Practical Arithmetic, in which I have endeavoured, through the whole, to have the rules as concise and familiar as the nature of the subject will permit. During the long period which I have devoted to the instruction of youth in Arithmetic, I have made use of various systems which have just claims to scientific merit; but the Punthors appear to have been deficient in an important bpoint-the practical teacher's experience. They have been 100 sparing of examples, especially in the first rudiments; din consequence of which, the young pupil is hurried through e the ground rules too fast for his capacity. This objection I have endeavoured to obviate in the following treatise. In teaching the first rules, I have found it best to encourage the attention of scholars by a variety of easy and familiar questions, which inight serve to strengthen their tuinds as their studies grew more arduous. The rules are arranged in such order as to introduce the inost simple and necessary parts, previous to those which are more abstruse and difficuit. To enter into a detail of the whole work would be tedious; I shall therefore notice only a few particulars, and refer the reader to the contents. . Although the Federal Coin is purely decimal, it is so nearly allied to whole numbers, and so absolutely necessary to be understood by every one, that I have introduced it iminediately after addition of whole numbers, and also shown how to find the value of goods therein, immediately after simple multiplication; which may be of great advarro tage to many, who perhaps will not have an opportunity of learning fractions. In the arrangement of fractions, I have taken in ener new methodl, the aiva; tages and facility of we mifficiently npologize fr its not isoluç 2 systems. As decimal frictions may be learned much easier than vulgar, and are more simple, useful, and necessary, and soonest wanted in more useful branches of Arithmetic, they ought to be learned first, and Vulgar Fractions omitted, until further progress in the science shall make them necessary. It may be well to obtain a general idea of them, and to attend to two or three easy problems therein; after which, the scholar may learn decimals, which will be necessary in the reduction of currencies, computing interest, and many other branches. Besides, to obtain a thorough knowledge of Vulgar Fractions, is generally a task too hard for young scholars who have made no further progress in Arithmetic than Reduc. tion, and often discourages them. I have therefore placed a few problems in Fractions, ac cording to the method above hinted; and after going throuyh the principal mercantile rules. have treated upon Vulgas Fractions at large, the scholar being now capable of going through them with advantage and ease. In Simple Interest, in Federal Money, I have given several new and concise rules ; some of which are particularly designed for the use of the compting-house. The Appendix contains a variety of rules for casting Interest, Rebate, &c. together with a number of the most casy and useful problems, for measuring superficies and solids, examples of forms commonly used in transacting business, useful tables, &c. which are designed as aids ir the common business of life. Perfect accuracy, in a work of this nature, can hardly be expected ; errors of the press, or perhaps of the author inay have escaped correction. If any such are pointei! put, it will be considered as a mark of friendship and sa Tour, by The public's most humble NATHAN DABOLL TABLE OF CONTENTS. AUDITION, Simple, of Federal Money, Compound, Comission, Evolution or Extraction of Roots, Federal Money, Subtraction of, |