An abacus is a hand-operated calculating tool used since ancient times in various parts of the world, including the ancient Near East, Europe, China, and Russia, millennia before the adoption of the Hindu-Arabic numeral system. It is a mechanical aid used for counting and performing mathematical operations such as addition, subtraction, multiplication, and division. The abacus consists of a two-dimensional array of slidable beads or similar objects, which can be loose on a flat surface or sliding in grooves. Later designs have the beads sliding on rods and built into a frame, allowing faster manipulation. The abacus has an advantage of not requiring a writing implement and paper or an electric power source. Although calculators and computers are commonly used today instead of abacuses, abacuses remain in everyday use in some countries.
The abacus can also calculate roots up to the cubic degree. It is traditionally made of various types of hardwoods and comes in varying sizes. The frame of the abacus has a series of vertical rods on which a number of wooden beads are allowed to slide freely. A horizontal beam separates the frame into two sections, known as the upper deck and the lower deck. Each bead in the upper deck has a value of 5, while each bead in the lower deck has a value of 1.
The abacus was first used by the Babylonians as early as 2,400 B.C. and was in use in Europe, China, and Russia, centuries before the adoption of the written Hindu-Arabic numeral system. Although the abacus is no longer used as widely as it once was, it is still a trusted tool used by shopkeepers in Asia and Chinatowns in North America, as well as by merchants, traders, and clerks in parts of Eastern Europe, Russia, and Africa. Another popular use of abaci around the world is to teach arithmetic to children, especially multiplication.
