The cardinal numbers in Italian follow a spelling pattern. Be careful, spelling can be tricky!

Table 5-1

Writing Numbers in Italian

All of these numbers are invariable except zero and uno. The number uno has the same forms as the indefinite article. Un amico can mean a friend or one friend, depending on the context. The plural of zero is zeri.

Ci sono due zeri nel numero di telefono.

There are two zeros in the phone number.

When -tre is the last digit of a number larger than twenty, the final -e of -tre is accented.

ventitrè, trentatrè, quarantatrè

Numbers from venti to novanta drop their final vowel before adding uno or otto.

ventuno, trentotto, novantuno

The numbers ventuno, trentuno, and all the way up to novantuno usually drop the final -o when followed by a noun.

Mio fratello ha quarantun anni.     My brother is forty-one years old.

When followed by the word anni, the numbers venti, trenta, and all the way up to novanta usually drop the final vowel.

Mio nonno ha ottant'anni.     My grandfather is eighty years old.