Rapid Calculations

ARITHMETIO is not a subject about which the average man would wax enthusiastic, nor is it one about which he knows much. It is hardly considered worthy the attention of serious College students, and is one of the few subjects on which no professorship, lectureship or readership exists at our Universities. Yet it is of great importance to most of us in our daily lives. Men have frequently to make calculations in connection with their occupations, while women are daily confronted with bills and tradesmen's accounts that need checking. Most of us, in doing these calculations, still use the methods taught us in our early childhood-methods which are no doubt simple and suitable for small children, but which are slow and incapable of wide application. How many men, for instance, could say with certainty how much should be taken off a bill if 3! per cent discount were allowed 1 Or how many housewives could rapidly check the butcher's statement that the price of the joint weighing 5 lbs. 3 oz. at Is. 5id. per lb. is 7s. 6!d. 1 Arithmetic is one of the oldest of the Sciences, but, like all others, it has advanced in recent years. In this book my brother has set out some of the newer methods of computation, including some which he has himself devised, and it will be seen that they are much more rapid than the ordinary methods, and that the results can readily be checked. Naturally some time and trouble are necessary for mastering them, but people who have to make calculations without the comfort of the slide rule or the luxury of the calculating machine will soon recover all the time spent, and for the rest of their days will be the gainers. This little book is offered as the experience of one who has successfully taught many pupils, who knows their capacities and the kind of tasks they are likely to have subsequently to do. It is a serious effort to make this humdrum, ordinary, but very useful subject more useful by speeding up the work without sacrificing accuracy, and as such it deserves the attention of a wide circle of readers, and especially of teachers.