GrammarCollective Numbers

Russian has a special category of numbers (дво́е, тро́е, че́тверо...) used in specific contexts:

Male or mixed-gender groups

Collective numerals sound most natural with men or mixed groups:

• двое друзей - two (male/mixed) friends
• трое студентов - three students (at least one male)

With only women, normal numbers are preferred: две подруги, not двое подруг.

Children / young beings

Very common, even if gender is known:

• двое детей - two children
• трое котят - three kittens

This is more natural than два ребёнка in many contexts.

Plural-only nouns

Mandatory with nouns that have no singular:

• двое суток - two days (24h periods)
• трое ножниц - three pairs of scissors
• четверо очков - four pairs of glasses

You cannot use normal numbers here.