I was wondering if someone could explain this error? I typed in the sample code from the Haskell Beginning Wikibook to define a function for absolute value. I have GHC 7.0.4 for OSX. The error went away when I put parentheses around the negative value, so did the Haskell interpreter think I was entering - and a second argument, namely 10, when the parentheses weren't there? Thank you! *Main> let abs x = if x < 0 then -x else x *Main> abs 5 5 *Main> abs -10 And got the following error <interactive>:1:6: No instance for (Num (a0 -> a0)) arising from the literal `10' Possible fix: add an instance declaration for (Num (a0 -> a0)) In the second argument of `(-)', namely `10' In the expression: abs - 10 In an equation for `it': it = abs - 10