Is the word menos the same in Brazilian and European Portuguese?

Yes

The meaning, spelling, and grammatical function of "menos" are identical in both Brazilian and Continental Portuguese. It serves as an adverb to indicate a smaller quantity or degree, and as a preposition/adjective to denote subtraction or "fewer." The only distinction is in pronunciation:

• Brazilian Portuguese: The vowels tend to be more open, and the "s" sound varies by region (it can be a sharp [s] in São Paulo or a "sh" [ʃ] in Rio de Janeiro).
• Continental Portuguese: There is significant vowel reduction, meaning the "e" is often pronounced very short or nearly silent, and the "s" at the end of the word is almost always pronounced as a "sh" [ʃ] sound.

Brazilian Portuguese Examples

1. Eu tenho menos trabalho hoje. (I have less work today.)
2. Tem menos alunos na sala. (There are fewer students in the room.)
3. Eu quero menos açúcar no café. (I want less sugar in the coffee.)
4. O carro é menos rápido. (The car is less fast/slower.)
5. Você tem menos irmãos que eu. (You have fewer siblings than I do.)

Continental Portuguese Examples

1. Eu tenho menos trabalho hoje. (I have less work today.)
2. Há menos alunos na sala. (There are fewer students in the room.)
3. Eu quero menos açúcar no café. (I want less sugar in the coffee.)
4. O carro é menos rápido. (The car is less fast/slower.)
5. Tu tens menos irmãos que eu. (You have fewer siblings than I do.)