Exactly how "another one" would be translated into Italian depends on how you wish to use it. If the "one" being referred to is a male being or a masculine noun-object, you would say un'altro. If the "one" being referred to is a female being or a feminine noun-object, you would say un'altra.
"Little one" in English is piccolino in Italian.
Una in Italian means "a," "an," or "one" in English.
Mono in Italian means "one" in English."
"One time" in English is una volta in Italian.
"Crazy one" in English is un pazzo in Italian.
"One to 30" in English is da uno a trenta in Italian.
Un before a consonant in Italian means "a" or "one" in English.
"Dear one" in English is cara for a female and caro for a male in Italian.
numero uno
Il fortunato in Italian means "the lucky one" in English.
Un attimo in Italian means "one moment" in English.
Una ragazza in Italian means "a (one) girl" in English.