First, I'd like to state that I judge poorly this show for its first three seasons. Therefore I wouldn't know if it has improved or not since then.
The idea of a show combining crime and mathematics was great... Finally investigations that wouldn't rely on major breakthrough coming from nowhere. Mathematics are rational, I thought the show would have "kept it real".
I was disappointed by the lack of rationality "behind the maths". I studied mathematics for a long time now to know that (almost) everything can be modelized by mathematics, we may wonder about the relevance of the results though.
In Numb3rs (check out l33t language...) or Numbers, two worlds collide : the "real" one and the "theoretical" one. Lucky for us we can count on Charlie Eppes to bridge the two. How can he do such a thing? Some would argue that he is a genius, I would bet on the fact that he uses magic. Problem is maths aren't any kind of SFX you can turn around and throw as you like, there are several good things (I mean appropriate and well designed) in the show. It's the process as a whole that lacked consistency and credit.
I don't mind making fun of science (The Big Bang Theory), but don't make it sound like it's serious...