in russian grammar, the system of declension is elaborate and complex. nouns, pronouns, adjectives, demonstratives, most numerals and other particles are declined for two grammatical numbers (singular and plural) and six grammatical cases (see below); some of these parts of speech in the singular are also declined by three grammatical genders (masculine, feminine and neuter). this gives many spelling combinations for most of the words, which is needed for grammatical agreement within and (often) outside the proposition. also, there are several paradigms for each declension with numerous irregular forms.