finite decimal

A regular number, also called a finite decimal, is a positive number that has a finite decimal expansion. A number such as 1/3 = 0.33333... which is not regular is said to be nonregular. If r congruent p/q is a regular number, then r | = | a_1/10 + a_2/10^2 + ... + a_n/10^n | = | (a_1 10^(n - 1) + a_2 10^(n - 2) + ... + a_n)/10^n | = | (a_1 10^(n - 1) + a_2 10^(n - 2) + ... + a_n)/(2^n·5^n).

decimal expansion | nonregular number | repeating decimal