The part of the grammar page this lesson drills — read it here, then use it.
Један and два agree with gender
Један (one) is the only cardinal number that behaves like an adjective all the way through: један (masculine), једна (feminine), једно (neuter) - and, like an adjective, it also takes case endings, so as a direct object it becomes једну (feminine) or једно (neuter); the masculine form becomes једног only when the noun is animate (a person or animal) and otherwise stays један. Два (two) has a simpler two-way split: два for masculine and neuter, две for feminine. Три and четири never change for gender.
„Имам једну сестру.“ (I have one sister.) puts један into the feminine accusative једну, agreeing with сестру.
Special cases - the noun-count rule
After 1, the noun stays in its normal singular form: један сто, једна сестра. After 2, 3 or 4, the noun takes a special counting form - for masculine and neuter nouns this looks like the genitive singular (сто → стола), for feminine -а nouns it looks like the nominative plural (сестра → сестре). After 5 and up, the noun takes the genitive plural (сто → столова, сестра → сестара).
For compound numbers, only the last digit decides the form: двадесет један сто (21) behaves like 1, двадесет два стола (22) behaves like 2–4, двадесет пет столова (25) behaves like 5+ - however large the whole number is. The teens (11–20) are the one exception: they always take the 5+ genitive-plural form, regardless of what they end in.
| Number | Masculine (sto) | Feminine (sestra) | Neuter (selo) |
|---|---|---|---|
| 1 | sto | sestra | selo |
| 2–4 | stola | sestre | sela |
| 5+ | stolova | sestara | sela |