The most commonly used decimals are terminating decimals (decimals that stop, such as 0.5 or 0.74). A repeating decimal is a decimal that continues on indefinitely and repeats a number or block of numbers in a consistent manner, such as 0.666 … or 0.232323 … . A vinculum (a horizontal line over the number or numbers) is the standard notation used to show that a number or group of numbers is repeating. Using the vinculum, the repeating decimal looks like

. Some books put the vinculum below the number, but this is less common.