Why abacus is considered as first computer?
First and foremost we will look at the History of abacus. Abacus is more than 5000 years old. Before the Electronic calculators were invented Abacus was the only calculating device available for performing the arithmetic operation of addition, subtraction, multiplication and division. By manipulating the beads of the abacus all the above functions could be performed without any limitations in the number of digits. Abacus was the manual computer of the ancient era we can say.
The modern computer is an electronic device which not only performs the arithmetic calculations but performs various other functions using a different language. Hence if we see the history of abacus and computer abacus is a tool with beads used for all basic arithmetic calculations and the computer is an electronic device which performs not only the above operations but also connects people around the world using different language or programs.