How to make a simple Calculator

Abacus is a Latin word that has its origins in the Greek words abax or abakon (meaning “table” or “tablet”) which in turn, possibly originated from the Semitic word abq, meaning “sand”. The abacus is one of many types of counting devices which are used to count large numbers. Why does the abacus exist?

It is difficult to imagine counting without numbers, but there was a time when written numbers did not exist. The earliest counting device was the human hand and its fingers, capable of counting up to 10 things…