12.2. Ordinal numbers

Ordinal numbers indicate the order or position of something  (in English they are “first, second, third...fourteenth, fifteenth, etc.” Italian ordinal numbers are irregular from first to tenth, and they always function like an adjective: they must agree in gender and number with the noun they modify, e.g.,

il primo negozio = the first store

la prima borsa = the first bag

i primi soldati = the first soldiers

le prime luci = the first lights

Following are the ordinal numbers, “first” through “tenth” in their natural state (ending in –o)

For every ordinal number beyond “tenth,” you simply elimate the final vowel from the cardinal number and add –esimo/a/i/e.

la quarantesima maratona (quaranta + esima)

the fortieth marathon

il quindicesimo piano (quindici + esimo)

the fifteenth floor

il venticinquesimo compleanno (venticinque + esimo)

the twenty-fifth birthday

If your ordinal number ends in a “three” like twenty-third, ventitreesimo, then you double the E:

trentatreesimo = thirty-third

Fractions are expressed in Italian with cardinal numbers first, and then ordinal numbers (this is what we do in English, also):

due terzi = two-thirds

quattro quinti = four-fifths

However a fraction with “one” in the beginning is written with un:

un terzo = one third

un quinto = one fifth