Regular and non-regular numbers are actually other terms for rational numbers. Regular numbers are positive integers that have a finite decimal expansion. In other words, a number that seems to “end.” For example, one quarter (1/4) is equal to the decimal equivalent of 0.25, in which the numbers end with the “5.” A non-regular number is one that includes repeating decimals—numbers that seem to go on forever. For example, one third (1/3) is equal to the decimal equivalent of 0.3333…, in which the number 3s go on indefinitely.