A New Way of Multiplying by 9
Suppose it be required to multiply the following figures by 9, the result may be obtained in the following as well as in the ordinary way. In the first example the ordinary method has been pursued; the new way consists in adding a 0 on the right-hand side of the figures, and subtracting the number to be multiplied.
467543 9 _______ 4207887
4675430 467543 _______ 4207887