I'm not the commenter you're replying to, but I've often found the Haskell numeric classes (Num, Fractional, Integral etc) prickly. The almost, but don't quite, map to (mathematical) algebraic structures.
Having use Haskell for math programming, I agree with this sentiment. Haskell's standard classes are in an uncanny valley of matching the mathametical structures.
If you want to do that sort of thing with Haskell, I would suggest switching to the numeric prelude [0]
