The key to the tutor's guide: or, The arithmeticians repository : Containing the solutions of the questions, &c. that are in the guide; with the references as they stand in the second edition. To which is added (where necessary) some useful rules, &c. As those for the attaining a thorough knowledge of circulating numbers. Likewise an appendix, shewing the combination of quantities; the different ways they may be varied; with the method of filling the magic squares, &c. The whole being principally designed for the ease of school masters, and with the guide, furnishes a more complete and extensive system of arithmetic, than any extant; and will enable all those who are acquainted with the first principles, to attain a competent knowledge of the several rules, with ease and precision. By Charles Vyse, teacher of the mathematics, and master of the academy in Old Round Court, Strand.