In the beginning of mankind, one tool has lasted threw the century and is still used today. This tool was the calculator. The calculator is a machine which makes doing math and number work easier. The first calculator to historian's knowledge that was widely used was the Abacus. The Abacus was an ingenious counting device based on the relative positioning of two sets of beads that move on parallel strings. The first Abacus was so underdeveloped that you could only count up to 5. (Could you even think of using a calculator today that could only add up to five? I didn't think so.)
…
