Wúlǐshù bù néng xiěchéng liǎng ge zhěngshù de bǐ, tā de xiǎoshù bùfen wúxiàn bù xúnhuán.
An irrational number can't be written as a ratio of two integers, and its decimal part goes on forever without repeating.
Tips
mistakes
无理 here renders the English "irrational" word for word, and in mathematics it means "not a ratio of whole numbers". It has nothing to do with 无理 "unreasonable", as in 无理取闹.
usage
Together with the 有理数 "rational numbers" they make up the 实数 "real numbers".
