I would say it is math. I find it really fun to think logically and have one definite answer. Even if you have no clue how to solve the problem, you can still try and you might get the right answer if you keep trying. I think it is interesting that there are a lot of formulas but some of them don't even have to be remembered because you can get them by using another formula that you remember. Math could be so difficult to even understand what is going on, but I think that makes you think more, and that is why math is an important subject to learn.