Approximate French Numbers

When you want to make an estimate or take a guess, you can use approximate numbers. Most approximate French numbers are formed with the cardinal number, minus the final e (if any), plus the suffix -aine.


une huitaine   about eight [days] (about a week)

une dizaine   about ten (note that x in dix changes to z)

une douzaine   a dozen

une quinzaine   about fifteen [days] (about two weeks)

une vingtaine   about twenty

une trentaine   about thirty

une quarantaine   about forty

une cinquantaine   about fifty

une soixantaine   about sixty

une centaine   about a hundred

un millier   about a thousand


Approximate numbers are treated grammatically as expressions of quantity, and like all expressions of quantity, approximate numbers must be joined to the noun they modify with de.

une dizaine d'étudiants   about 10 students

une quarantaine de livres   about 40 books

des centaines de voitures   hundreds of cars

des milliers de documents   thousands of documents


Note that in English, it's typical to talk about "dozens" of something, whereas in French it's more natural to say dizaines rather than the literal equivalent douzaines:

des dizaines d'idées   dozens of ideas