Q: I just created a new cube
and I'm trying to change the number of divisions in the channel box but there are no inputs why?
A: You need to turn on construction history in order for Maya to keep track of such things. It's the little icon in the upper right side portion of the screen with the white page on it. If you're using a version previous to 2009, then the icon looks more like a scroll than a flat sheet of paper.