An abacus is a simple counting tool used for performing arithmetic calculations. It consists of a rectangular frame with rods or wires, each holding beads that can be moved back and forth. The position of the beads represents different values, allowing users to add, subtract, multiply, and divide numbers efficiently. Originating in ancient times, the abacus has been used in various cultures, including the Chinese and Roman civilizations. While modern calculators and computers have largely replaced it, the abacus is still taught in some schools to help students understand basic math concepts and improve their mental calculation skills.