Decimal is the base-10 notational system for representing real numbers. The expression
of a number using the decimal system is called its decimal
expansion, examples of which include 1, 13, 2028, 12.1, and 3.14159.
Each of the arabic numerals 0 to 9 is called a decimal digit, and the period placed to the right of the units place in a decimal number is called
the decimal point (or, in the case that a comma
is instead used for this purpose, the decimal comma).