There are so many different kinds of calculators.  There are mechanical, electromechanical, or electronic.  Either way everybody calls them calculators because they are all just adding devices.  They are devices that do basic math, such as add, multiply, subtract, and divide.

 The oldest calculator was called the abacus.  The abacus has been used for thousands and thousands of years.  It was made by little movable markers sort of strung or beaded on a wire or placed on a marked board.
 

    The abacus, which came to be 5000 years ago in a place called Asia Minor, is still in use today and might be thought of as the first computer ever.  The device allows its users to create computations with a system of sliding beads on a rack.  But when the use of paper and pencil started spreading in places like Europe, it lost its importance.  It took almost 12 centuries, though, for the next advance in computing devices to emerge!  That’s 1,200 years!  And you thought you were old!