I know you can convert a String to an number with read:
String
read
Prelude> read \"3\" :: Int 3 Prelude> read \"3\" :: Double 3.0
An example based on Chuck's answer:
myIntToStr :: Int -> String myIntToStr x | x < 3 = show x ++ " is less than three" | otherwise = "normal"
Note that without the show the third line will not compile.
show