I posted this on another thread about Superman's intellect, and I think it holds valid here:
I'm going to argue that being a genius doesn't mean you can't be naive and also fall for traps. I mean...
...who doesn't know a nerd--really smart, well educated--that has fallen for a bully prank, or has gotten their head dunked in the toilet (or something to that effect)? From what I've seen, intellectuals are many times the butt of jokes and the most gullible people on the planet.
Superman is not clever like Lex, nor does he have the creativity. He's not a detective like Batman; the boy lacks street-smarts. But, he can comprehend book-smarts--theories, languages, mechanics, math--these types of things that require very little bias to understand.
Think about it. Superman is all about truth and justice--he's extremely idealistic. Wouldn't it make sense that his intellectual strength lies in fields that are prone to find absolute truths like math and science?