problem with animate() and " + "

problem with animate() and " + "

Hi folks,

I'm trying to consolidate a lot of individual functions which scroll the content of a div. Here's an example:

      $('#updown').animate( {marginTop:'-40rem'}, 2000);

I've tried several versions of

function upIt(n,t) {
$("#updown").animate( {"marginTop:" + "  'n'  "  "rem"}, "t");
}

but  get error messages about "+".  What am I missing ?

cheers.