Just appears blank where the total should be. Could it have something to do that not all those fields are going to always have a number in them?

What I mean is, that one one record it might have cardqty1 through cardqty10, and another detailed page another record might have cardqty1 through cardqty30 and so on and so on. No way to tell on each page until ti's loaded. Don't know if this makes a difference or not. But at the moment <%total_cardqty%> is just showing a blank spot.