Take four blocks and lay them in front of a child close together. Then take four more of the same size blocks and lay them out, but spaced further apart. Ask the child which has more? The child that hasn't developed conservation of numbers, will say that the longer one has more. I tried it with different objects and with different terminology. She simply hasn't developed conservation yet. Cognitive science has come a long way since Piaget, but he got conservation right.
I had grand plans of teaching my child mathematical thinking at an early age before I ran into conservation. I think we will just work on counting and recognizing numbers for a few months then try again after she is four (or after 5). Maybe this will help prevent a math revolt like CC had?