Device for teaching young children elementary multiplication

摘要

334,319. Montessori, M. July 9, 1929. Abacuses. - A device for teaching young children multiplication consists of a rectangular frame adapted to be used on a flat or inclined surface and provided with a series of spaced wires b, each having threaded upon it ten beads c, and a series of noughts permanently represented at the foot of each wire or a number of adjacent wires starting from the right, so that when a number represented on a piece of paper &c. with the digits spaced apart the same distance. as the wires is slid along the bottom member a' of the frame from right to left, the noughts appear in turn at the right hand of the number, representing successively the number as multiplied by increasing powers of ten. On the top member a2 of the frame starting from the right are the numbers 1, 10, 100, &c. On the side member a of the frame are four squares d, d1, d2 and d3 adapted to be used in conjunction with four sets of numbers printed on a piece of cardboard &c., each set containing the numbers 1 to 9, and each set corresponds with the colour of one of the squares. The frame has a background of any material upon which are drawn the lines f, f1, f2 and f3 from each one of the squares to one of the wires b. The beads, squares, sets of numbers, and the numbers marked on the top of the frame may be differentiated from each other by colour.