A key to The complete practical arithmetician. [electronic resource] : Containing answers to all the questions in that work, with the solutions at full length, wherever there is the smallest Appearance of Labour or Difficulty; The Whole Interspersed With Several useful Notes and Observations. To which is added, an appendix, Containing, A Synopsis of Logarithmical Arithmetic, Shewing their Nature, Construction, and Use, in the plainest Manner possible. Tables of Compound Interest and Annuities, Extending from One to Forty Years. Also, General and universal Demonstrations of the principal Rules In The Complete Practical Arithmetician. The whole together forming the most Complete System of Arithmetic extant, both in Theory and Practice. By Thomas Keith, Teacher of the Mathematics, Author of a Short and Easy Introduction to the Science of Geography, the Complete Practical Arithmetician, &c.