Welcome to Haskell, where anything can be infix :-)
(+) 4 2
vs.
(+) <$> Just 4 <*> Just 2
I usually prefer the applicative style above to liftA2 (+) (Just 4) (Just 2)
because it preserves the "form" of the original expression and generalizes to more arguments. ie. it doesn't require liftAn for whatever n number of arguments my function takes.