What are the advantages of using a calculator over an abacus?

The abacus as a treasure left behind by our ancestors, calculators in the addition and subtraction of the abacus dominant, in the multiplication and division of the calculator dominant, the abacus for addition and subtraction of the number of operations fast, but if there is a multiplication and division of the law, then it is much slower, not as fast as the calculator, the mental calculation of the most accurate, the abacus use of the mental calculation of the speed of fast, but also high.