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
Dot-decimal notation table in RFC 790 ("Assigned Numbers") used the dotted decimal format, zero-padding each number to three digits. RFC 1123 ("Requirements for Internet Hosts – Application and Support") from October 1989 mentions a requirement on host software to accept “IP address in dotted-decimal ("#.#.#.#") form”, although it notes “[t]his last requirement is not intended to specify the complete syntactic form for entering a dotted-decimal host number”. A separate IETF draft to define textual representation of IP addresses expired. A popular implementation of IP networking, originating in 4.2BSD, contains a function "inet_aton()" for converting IP addresses in character string representation to internal