An abacus is a traditional calculating tool, that has been used for centuries across various cultures, particularly in Asia. 
 
It consists of rows of movable beads strung on rods. These beads are divided into two sections by a central beam, with each section representing different numerical values. 
 
Users perform calculations by moving the beads, enabling them to conduct basic arithmetic operations like addition, subtraction, multiplication, and division. 
 
The abacus is notable for its simplicity and efficiency, allowing for quick mental calculations once the user is skilled in its operation.