The choice between Real or Decimal numbers is important. Both can
hold large numbers with a certain amount of precision, but there
are fundamental differences between the two types of numbers:
- Real numbers are designed for speed in calculations where accuracy is not so important and where a close value is good enough.
- Decimal numbers are designed to provide a bound to the error you are willing to accept, sacrificing some performance if it is needed to guarantee the accuracy.
These differences become especially important when dealing with
money. As a rule, whenever you are handling numbers that represent
money, use Decimal numbers.