The abacus is the most ancient calculating device known. It has endured over time and is still in use in some countries. An abacus consists of a wooden frame, rods, and beads. Each rod represents a different place value-ones, tens, hundreds, thousands, and so on. Each bead represents a number, usually 1 or 5, and can be moved along the rods. Addition and subtraction can easily be performed by moving beads along the wires of the abacus.

The word abacus is Latin. It is taken from the Greek word abax, which means "flat surface." The predecessors to the abacus-counting boards-were just that: flat surfaces. Often they were simply boards or tables on which pebbles or stones could be moved to show addition or subtraction. The earliest counting tables or boards may simply have been lines drawn in the sand. These evolved into actual tables with grooves in them to move the counters.

Since counting boards were often made from materials that deteriorated over time, few of them have been found. The oldest counting board that has been found is called the Salamis Tablet. It was found on the island of Salamis, a Greek island, in 1899. It was used by the Babylonians around 300 B.C.E. Drawings of people using counting boards have been found dating back to the same time period.

There is evidence that people were using abacuses in ancient Rome (753 B.E.C. - 476 C.E.). A few hand abacuses from this time have been found. They are very small, fitting in the palm of your hand. They have slots with beads in them that can be moved back and forth in the slots similar to counters on a counting board. Since such a small number of these have been found, they probably were not widely used. However, they resemble the Chinese and Japanese abacuses, suggesting that the use of the abacus spread from Greece and Rome to China, and then to Japan and Russia.

An adapted abacus, invented by Tim Cranmer, called a Cranmer abacus is still commonly used by individuals who are blind. A piece of soft fabric or rubber is placed behind the beads so that they do not move inadvertently. This keeps the beads in place while the users feel or manipulate them.

Learning to use the abacus, realize there are different types of abacus'. For example, the classical abacus or Chinese abacus has five beads on the bottom and two beads at the top. The modern abacus, Japanese abacus, or soroban has four beads at the bottom and one bead at the top.

This begins our Computer Systems History; the abacus, also called a counting frame, is a calculating tool – the first known calculator, was invented in Babylonia 2400 BC. It was used primarily in parts of Asia for performing arithmetic processes.

A tally stick was an ancient memory aid device to record and document numbers, quantities, or even messages. individual in performing mathematical calculations.

The abacus in the form we are most familiar with was first used in China in around 500 B.C