Abacus for performing arithmetic operation e.g. addition, has ten beads installed on each rod and numbered, from side having digits zero, such that numbers one to nine are represented on respective nine beads, and number zero on tenth bead

摘要

The abacus has three rods (2) installed in a rectangular frame (1) and perpendicular to a side (1a) of the frame carrying three 0 digits (4). Ten beads (3) are installed on each rod and are numbered from the side such that numbers 1 to 9 are represented on the nine beads of each rod, respectively, and the number 0 is on the tenth bead of each rod.