list1 ++ list2

oldNumbers = [1,5,14,22,37]
 newNumbers = [3,10,17,27,34,69]
 allNumbers = oldNumbers:newNumbers

error:
    * Non type-variable argument in the constraint: Num [a]
      (Use FlexibleContexts to permit this)
    * When checking the inferred type
        allNumbers :: forall a. (Num a, Num [a]) => [[a]]