In 1642 a French student invented the first mechanical calculator. He was only 18 and the counting machine was a present for his father. The father worked as a tax collector and the young man wanted to make his job easier.
The talented inventor made several machines, but nobody was interested. The young man was ahead of his time. Many years passed before people realized how useful these machines could be and started mass producing them.
Today most mechanical calculators have been replaced with electronic models. These small devices can perform a lot of mathematical operations. You just need to enter the numbers by pressing the keys and you’ll see the final result on the screen in no time.