An abacus is an ancient manual calculator used for performing mathematical calculations. It works by manipulating beads on rods or wires within a frame. Here's a breakdown of its key aspects: History: Abacuses have been around for thousands of years, used in various civilizations like Mesopotamia, China, and Rome. They were the primary tool for calculations until the widespread adoption of the Hindu-Arabic numeral system. Design: A typical abacus has a rectangular frame with multiple rods or wires. Each rod is strung with beads, separated by a divider into upper and lower sections. The position of the beads on the rods represents numerical values. Calculations: By moving the beads up and down the rods according to specific rules, you can perform basic arithmetic operations like addition, subtraction, multiplication, and division. Some abacuses can even handle more complex calculations like roots. Modern Use: While electronic calculators have largely replaced abacuses for everyday calculations, they are still used in some parts of the world, particularly in Asia. Additionally, abacuses are gaining popularity as educational tools, believed to improve mental math skills and concentration.