A new system of practical arithmetic : In three parts. Part I. Contains all the fundamental rules; with new observations relating to integers, vulgar fractions, and decimals. Part II. Contains the most useful rules of proportion, with their application to trade; a compendium of mensuration; and several curious algebraical rules. Part III. Contains demonstrations of the principal rules; and a complete set of tables, with their construction and use. Calculated for the use of schools, and men of business. The second edition. By William Scott, teacher in Edinburgh.