fractions 1/2, 1/3 and 1/4 have proper names (nouns): and , which are used instead of ordinal numbers. they are also often added with preposition , while form of noun appears to be related to the integer part rather than to the fraction: [instr.] [gen.] "10 1/4 turns". prefixes (with genitive) and (with nominative) are used for "half" of something: (half of a lemon), полчаса́ (half an hour; but: ); (half moon, crescent). words with are not declined, and there is a set of rules for writing with or without dash.