We used sidewalk chalk to construct a numberline, and then had DD step/count problems (both addition and subtraction) as a way of understanding this process when she was around 4, I think.
So it wasn't necessarily something that only works with visual-spatial learners. It can work on a kinesthetic front, as well.
Bottom line, though, is that she really only "got" this when she was developmentally ready. Until then, one has to just figure out a work-around strategy for the developmentally inappropiate/underdeveloped skill.
