In Italian, indefinite articles are words that take the meaning A or AN, when paired with a noun. As in English, indefinite articles refer to a general object or when the identity is unknown.
Indefinite articles have no plural form, but like other articles and adjectives, they must agree in gender with nouns. Like definite articles, indefinite articles always come before the noun.

Examples:

• Marco sta mangiando un'insalata.          >>      Marco is eating a salad.
• Una donna ti ha telefonato.                       >>      A woman phoned you.
• C'è un albero grande nel giardino.          >>      There is a big tree in the garden.   (NB: adjectives typically come after the noun in Italian)
• Ti posso offrire un caffè?                            >>      Can I offer (buy) you a coffee?
• Devo comprare uno zaino.                         >>      I need to buy a backpack.

​In the above examples,  the articles un', una, un, uno refer to indefinite (non-specific) objects or unknown persons.

Rules for using indefinite articles:

Indefinite articles are not used with proper nouns (ex: Londra, Roma, Mario, Anna...) with the exception of brand names to refer to a specific product: (ex: una Ferrari, un Xbox...).

Pratica!

ESERCIZI/EXERCISES
Review Gender of Nouns, if necessary.