Qusसबसे पुराना गणना करने वाले उपकरण हैं
A. Abacus
B. Clock
C. calculator
D. None of these.
Solution
A. AbacusExplanation
Abacus, plural abaci or abacuses, calculating device, probably of Babylonian origin, that was long important in commerce. It is the ancestor of the modern calculating machine and computer.