![]() The Russian version of the abacus has many horizontal rods with moveable, undivided beads, nine to a column. These two abaci are slightly different from one another, but they are manipulated and used in the same manner. A Chinese suan pan has two heaven and five earth beads, and the Japanese soroban has one heaven and four earth beads. Each heaven bead has a value of five units and each earth bead has a value of one unit. Courtesy of Gale Group.īeads, and beads below are called earth beads. Beads above the crossbar are called heavenĪ Chinese abacus called a suan pan (reckoning board). The moveable beads are located either above or below the crossbar. A horizontal crossbar is perpendicular to the rods, separating the abacus into two unequal parts. For example, starting from the right and moving left, the first rod represents ones, the second rod represents tens, the third rod represents hundreds, and so forth. Each rod represents columns of written numbers. The abacus is based on the decimal system. Within the rectangle, there are at least nine vertical rods strung with movable beads. It is rectangular, often about the size of a shoe-box lid. ![]() Some scientists think that the term abacus comes from the Semitic word for dust, abq.Ī modern abacus is made of wood or plastic. ![]() Number symbols were marked and erased easily with a finger. Were shallow trays filled with a layer of fine sand or dust. The heaven beads have five times the value of the earth beads below them. The first abaciĪn example of addition on a suan pan. Before the invention of counting machines, people used their fingers and toes, made marks in mud or sand, put notches in bones and wood, or used stones to count, calculate, and keep track of quantities.
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