thanks Doulingo for teach me maths ;)
"Duas menos duas" was counted wrong. Is "two" always masculine unless it is accompanying a feminine noun?
No, "duas menos duas" should be accepted.
Posso usar "igual" por "é"?
You can use it as long as you say: "igual a.."
Dois menos dois, igual a zero.
Muito obrigada, RC_BR. A sua ajuda está muito útil. :)
Ou "dois menos dois é igual a zero".
Why is "2-2=0" wrong?
That's the language of mathematics which isn't being taught here. Rather, how mathematics is said in the perspective languages.
dois menos duas why wrong?
In portuguese two must follow the gender. Dois is masculine and duas is feminine. In your sentence you are mixing the gender and that is incorrect.
Talvez seja uma coisa de Minas, mas geralmente falamos dois menos dois DÁ zero ao invés de É zero.
Not just in Minas, I am sure, as the equivalent English is often used in the UK. I think using 'gives' emphasizes that the end result is a consequence of the earlier operations. (Not much of a gift here, I know!)
why is "dois sem dois é zero" wrong?
"Sem" means "without." One would not say "Two without two is zero." in English; one should not say it in Portuguese either. :)
Dois menos dois faz zero? In English we can say 2 minus 2 makes zero.
But not in Portuguese... "faz" does not work here...