GrammarFractions and Decimals

Russian fractions are a "grammar sandwich": The numerator is a cardinal number, and the denominator is an ordinal number.

• одна вторая - one half
• две третьих - two thirds
• три четверти - three quarters

The "Half" Family: There is пол- (half), полови́на (a half), and the very common полтора́ (one and a half). Note that полтора́ has its own unique declension!

• полчаса - half an hour
• половина дома - half of the house
• полтора часа (masc/neut) - one and a half hours
• полторы минуты (fem) - one and a half minutes
• с полутора часами - with one and a half hours
• к полутора дням - to one and a half days

Decimals: Russians use a comma rather than a point (e.g., 1,5 instead of 1.5).

• 1,5 → одна целая и пять десятых - "one whole and five tenths"
• 2,75 → две целых и семьдесят пять сотых - "two whole and seventy-five hundredths"

Case Agreement: Fractions govern the Genitive, singular if it ends in 1 but not 11, otherwise plural.

• одна вторая часа → Genitive Singular
• две третьих часов → Genitive Plural
• три четверти килограммов → Genitive Plural