nominal declension is subject to six cases – nominative, genitive, dative, accusative, instrumental, and prepositional – in two numbers (singular and plural), and absolutely obeying grammatical gender (masculine, feminine, and neuter). up to ten additional cases are identified in linguistics textbooks, although all of them are either incomplete (do not apply to all nouns) or degenerate (appear identical to one of the six simple cases). the most recognized additional cases are locative ( — in the forest, on the bridge, in tears), partitive ( — (some) tea, sugar, cognac), and several forms of vocative ( — (oh) lord, god, father). the adjectives, pronouns, and the first two cardinal numbers further vary by gender. old russian also had a third number, the dual, but it has been lost except for its use in the nominative and accusative cases with the numbers two, three and four ("e.g." , "two chairs", now reanalyzed as genitive singular).