A repeating decimal is a decimal number that has a digit or a group of digits that repeat infinitely. For example, the decimal representation of the fraction 1/3 is 0.333..., where the digit "3" continues forever. This can also be written as 0.3̅, indicating that the "3" repeats. Repeating decimals can be classified into two types: pure and mixed. A pure repeating decimal has all digits after the decimal point repeating, like 0.666... (or 0.6̅). A mixed repeating decimal has a non-repeating part followed by a repeating part, such as 0.1̅2, where "2" repeats after the "1."