Practical arithmetick : in four books. I. Whole numbers, weights and measures. II. Fractions, vulgar and decimal. III. Mercantile arithmetick. IV. Extraction of roots, progression, &c. : Extracted from the large and entire treatise, and adapted to the commerce of Ireland, as well as that of Great-Britain. For the use of schools. / By John Gough, author of the Practical English grammar. ; Carefully revised by Thomas Telfair, philomath. ; And now fitted to the commerce of America. ; With an appendix of algebra, by the late W. Atkinson, of Belfast.