Decimal numbers that may be expressed as a fraction, the denominator of which is a power of ten. For example, the numerals formula_5 represent the fractions , , . More generally, a decimal with digits after the separator represents the fraction with denominator , whose numerator is the integer obtained by removing the separator. Expressed as a fully reduced fraction, the decimal numbers are those, whose denominator is a product of a power of 2 by a power of 5. Thus the smallest denominators of decimal numbers are The "integer part", or "integral part" of a decimal is the integer written
Decimal digits after the decimal separator, such as in " is the approximation of to "two decimals"". The numbers that may be represented in the decimal system are the decimal fractions, that is the fractions of the form , where is an integer, and is a nonnegative integer. The decimal system has been extended to "infinite decimals", for representing any real number, by using an infinite sequence of digits after the decimal separator (see Decimal representation). In this context, the decimal numerals with a finite number of non–zero places after the decimal separator are sometimes called "terminating decimals". A repeating decimal,