In Portuguese there are two ways to say “two”: dois and duas. Dois is masculine and duas is feminine.
Don’t be fooled! The word dos does exist in Portuguese, but it has nothing to do with the number two. It’s a contraction of the words de and os (“of” and “the”). For example, dos Santos, a common last name in Brazil, doesn’t mean “two saints” but rather “of the saints” or de los Santos in Spanish.
English: Two tickets, please.
Spanish: Dos billetes, por favor.
Portuguese: Dois bilhetes, por favor.
English: I have two daughters.
Spanish: Tengo dos hijas.
Portuguese: Eu tenho duas filhas.