Decimal is the base-10numeral system for representing real numbers. The term
"denary" is also used for this system in computer science education, although
"decimal" is the more traditional name (Langfield and Duddell 2019). 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).