[Haskell-cafe] weired

The following function which converts a number represents a sum of money in pence didn't work as expected and the result didn't make any sense to me: penceToString :: Price -> String penceToString p = let str = show p len = length str in if len ==1 then "0.0" ++ str else if len ==2 then "0." ++ str else (take (len-2) str) ++ "." ++ (drop (len - 2) str ) *Main> penceToString 234566666667899999999786 "-6710990.94" ?!?! -- X.W.D