As I think you´re learning Haskell, I´m just giving some hints: There is a function for dropping elements: http://zvon.org/other/haskell/Outputprelude/drop_f.html Also there is similiar a "take" which may helps you with "reverse". And for multiplying everything you might want to use a fold: http://zvon.org/other/haskell/Outputprelude/foldr_f.html best regards Leonhard