some rational numbers, such as 1/10, need a finite number of digits after the decimal point to write them in decimal form. the number one tenth is written in decimal form as 0.1. numbers written with a finite decimal form are rational. some rational numbers, such as 1/11, need an infinite number of digits after the decimal point to write them in decimal form. there is a repeating pattern to the digits following the decimal point. the number one eleventh is written in decimal form as 0.0909090909 ... .