I understand about the units, and rod blocks in MUS and Shiller not being visualizable, but the cardstock pieces in RS aren't either. The kids were able to understand what all those drawn units on the boxes were once they were actual 3-D objects. I'm not saying that having the base 10 set would help on it's own, but together, the "aha" was understood, and we could move on. Somehow, actually manipulating the pieces made more sense than a drawn on paper box representation of 100 or 1000. Any other suggestions of getting this concept across instead of using a base 10 set? How about a geometric volume set? I still can't figure out if my left overs will fit into a container or visualize a room plan of furniture placement, or organizing a shelf with different objects unless I actually do it....so I never move my furniture around ; ) understanding space and volume is such a deficit for me, and I thought, in the future I'd get a set of plastic geometric volume set, which are different than my geometric solid set. We really, really enjoy RS math otherwise, and look forward to completing, and continuing with Geometry.
Linette