Plainfield Academy, April 20, 1802. I MAKE use of DABOLL'S SCHOOL MASTER'S ASSISTANT, in teaching common Arithmetic, and think it the best calculated for that purpose of any which has fallen within my observation. JOHN ADAMS, Rector of Plainfield Academy. (Now Principal of Philips' Academy, Andover, Mass.] Billerica Academy, (Mass.) Dec. 10, 1807. Having examined Mr. DaBOLL's System of Arithmetic, I am pleased with the judgment displayed in his method, and the perspicuity of his explanations, and thinking it as casy and comprehensive a system as any with which I am acquainted, can cheerfully recommend it to the patronage of Instructers, SAMUEL WHITING, Teacher of Mathematics. From Mr. Kennedy, Teacher of Mathematics. I BECAME acquainted with DABOLL'S SCHOOLMASTER'S Assistant, 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 ii. elementary tuition, to the great advantage and improvement of the student, as well as the ease and assistance of 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. ROGER KENNEDY New-York, March 20, 1811. The design of this work is to furnish the 'schools of the United States with a methodical and comprehensive system of 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 authors appear to have been deficient in an important point--the practical teacher's experience. They have been too sparing of examples, especially in the first rudiments; in consequence of which, the young pupil is hurried through 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 might serve to strengthen their minds as their studies grew more arduous. The rules are arranged in such order as to introduce the most simple and necessary parts, previous to those which are more abstruse and difficuit. To enter into a detail of the whole work would be todious; 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 immediately 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 advantage to many, who perhaps will not have an opportunity of learning fractions. In the arrangement of fractions, I have taken an entire new method, the advantages and facility of which will sufficiently apologize for its not being according # other systems. As decimal fractions 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 nccessary in the reduction of currencies, computing interest, und many other branches. Besides, to obtain a thorough knowledge of Vulgar Fractious, is generally a task too hard for young scholars who have made no further progress in Arithmetic than Reduction, and often discourages thein. I have therefore placed a few problems in Fractions, according to the method above hinted; and after going through the principal mercantile rules, have treated upon Vulgar 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 sevewl 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 easy and useful problems, for ineasuring superficies and solids, examples of forms commonly used in transacting business, useful tables, &c. which are designed as aids in 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, may have escaped correction. If any such are pointed out, it will be considered as a mark of friendship and frie cour, hy The public's most humble NATHAN DABOLI.. TABLE OF CONTENTS. ADDITION, Simple, of Federal Money, Compound, Annuities or Pensions, at Compound Interest, Coins of the United States, Weights of, Evolution or Extraction of Roots, by Decimals, Inverse Proportion, Involution, Loss and Gain, Multiplication, Simple, Application and Use of, Supplement to, Compound, Numcration, Practice, Position, Permutation of Qimntities, of Currencies, do. of Coin, 82, 86 90, 97 Rules for reducing the different currencies of the several United States, also Canada and Nova Scotia, cach to the par - Application of the preceding, Short Practical, for calculating Interest, 114 203 208 to reduce the currencies of the different States to Fede- Rebate, a short inethod of finding the, of any given sum, for Addition, Subtraction, and Multiplication, showing the number of days from any day of one month to the same day in any other mouth, showing the annount of ll. or 1 dollar, at 5 and 6 per cent. Compound Interest, for 20 years, showing the amount of il. annuity, forborne for 31 years or under, at 5 and 6 per cent. Compound Interest, 221 showing the present worth of 11. annuiiy, for 30 years, at 5 and 6 per ecul. Compound Interest, of Cents, answering to the currencies of the United 224 225 103 226 Weights of screral pieces of English, Portuguese, and French Gold Coins, in dollars, cents, and malls, |