The device that functioned as a calculator in ancient times developed by ancient Sumerians in 5,000 BCE?

• A. Abacus
• B. Quipu
• C. Napier's bones
• D. Astrolabe

Answer: (A)

The abacus works as a simple counting device that lets you perform arithmetic by moving beads or counters to represent numbers. In ancient Mesopotamia, Sumerians used counting frames and bead-like elements to lay out numbers and carry out operations, effectively acting as a manual calculator long before printed numbers or digital tools. By arranging and sliding the counters, you can add, subtract, multiply, and even divide with practice, making it a foundational tool for quick calculations.

Quipu is a knot-based system for recording data, not primarily a calculator. Napier's bones are a later invention (17th century) used to multiply and divide. The astrolabe is an astronomical instrument for measuring celestial positions, not a calculator. So the abacus best fits the idea of a device that functioned as a calculator in ancient times.