It is generally believed that numeral classifier languages such as Chinese have no productive way to encode the contrast between plurality and singularity. This paper shows that although bare nouns in Mandarin Chinese encode general number, the language uses reduplicate unit words (including classifiers and measure words) to express unit plurality, and uses non-reduplicate form of unit words to express unit singularity. Neither way of number encoding is compatible with a numeral. The paper shows that plural markers in Mandarin Chinese are structurally licensed by certain quantifiers. This work indicates that classifier languages use the morphological forms of classifiers themselves to express the singular-plural contrast productively, a new understanding of the forms of number markers in numeral classifier languages.