The large-sized abacus for plane surface professor

摘要

(57) Abstract Objective Depending on the thing which does the concrete display which is appealed to visual sense,Relation between four ball abacuses and decimal modulo, simply in beginnerYou make understand, use for the introduction part of abacus education. Constitution In computer of plate-like, channel and window in notch and backThe griddle it sticks. The ball which on the other hand inscribes the digit for calculation on the surfaceWith, to make multiplication and division and the symbolic board which inscribes rank, each oneThe magnet it sticks on back. As for the ball magnetism making the channel wear, suraido point, the symbolic board magnetism it makes the window wear according to need.