Question

1. Fifty states make up the U.S.A.
2. Fifty states compose the U.S.A.
3. Fifty states comprise the U.S.A.
4, The U.S.A. is composed of fifty states.
5. The U.S.A. consists of fifty states.
6. The U.S.A. is made up of fifty states.

(Are they all grammatical and the same?)

Answer 1

All are correct except #2. And yes, all mean the same thing.