Unlike the independent 'ten' (H6235 eser), this form appears only as the second element in compound teen-numbers: eleven through nineteen. It inflects for gender — asar with masculine nouns, esreh with feminine — following the well-known Hebrew pattern of 'reverse' gender agreement in numerals. When used in date formulas (the eleventh year, the twelfth month), it functions as an ordinal without any morphological change, a feature mirrored in Arabic where the teens also serve double duty. One textual oddity at 1 Kings 22:48 preserves a ketiv form that the Masoretes repointed as a form of asah (H6213, 'to make').