Cardinal numbers

How to build numbers from 21 to 99 (decina + numero)

Rule: in Italian you normally write these numbers as one word:

• 20–90 (the “tens”) + 1–9 (the “ones”)
• 21 = venti + uno → ventuno
• 35 = trenta + cinque → trentacinque

Spelling detail: the vowel drops before 1 and 8

This is the point that most learners miss.

• With uno (1) and otto (8), the tens often drop the final vowel (usually -a or -i).

100+ and 1000+: write them together (no spaces)

• Italian normally writes compound numbers as one word.
• 101 = cento + uno → centouno (not cento uno)
• 135 = centotrentacinque
• 220 = duecentoventi

Cento: small pronunciation/spelling cue with 80

A useful detail for reading and listening:

• Before ottanta (80–89), cento often loses the final -o:
• 180 = centottanta
• 281 = duecentottantuno

Million vs billion: milione/miliardo (don’t mix them up)

“Mille” vs “mila” (1000 vs 2000+)

• 1000 = mille
• 2000 = duemila (one word)
• 3000 = tremila, 10,000 = diecimila

Quick self-check (common pitfalls)

1. One word? ventuno, trentacinque, duecentoventi
2. Did the tens drop a vowel before 1 or 8? ventuno, ventotto
3. Plural -i where needed? due milioni, due miliardi
4. 1000 special form? mille (but 2000+ uses -mila: duemila)

Useful fixed expression: “una dozzina”

• una dozzina = 12 (a dozen)
• Example: Prendo una dozzina di uova. = “I’ll take a dozen eggs.”