How are your exams going?

It's grammatically correct, although I don't 'carry' is the word you mean. By the way, "is't" isn't a word. You need to write out "is it" (but you can write "it's" instead of "it is").

The verb "llevar" in Spanish is much more broad than "to carry" in English. Llevar has some pretty useful uses that we simply do not have in English. For this use of llevar in English I would think of the concept as "como te van los examines" or something like that. That way you can say it in English as "how are your exams going?"

"How about your exams?"

I want to ask a friend about his exams and I don't know how is the correct question.