"Matematyka nie musi być nudna."

Translation: Mathematics does not have to be boring.

[JamesTWils]

Could this sentence also be "mathematics must not be boring"?

[Euhan1]

The problem here springs from an idiosyncrasy of the English language, namely that "must not" is not the negation of "must".

Compare the sentences:
1 You mustn't throw stones.
2 It is not true that you must throw stones.

Polish on the other hand treats the negation of musieć "correctly" (in agreement with propositioal logic).

[Rainer176116]

What about "Mathematics need not to be boring."?

[candlelightener]

Totaly right