1·The recurring decimal 3.999... is also described as 3.9 recurring.
循环小数3.999...亦作3.9循环。
—— 《牛津词典》
2·Scores can also be expressed as a finite or infinite decimal recurring decimal.
分数亦可表示为有限小数或无限循环小数。
3·This paper, by studying and guessing, has advanced the concept of the characteristic value of the prime recurring decimal, and given a series of important propositions.