This paper discusses the question, what kinds of learning and new knowledge about content and children's thinking can an innovative curriculum program motivate? Discussion is restricted to whole number operations and how changing knowledge, beliefs, and practice as both an individual and collective problem might be conceived. To the extent that changes in practice are motivated by teachers' own concerns and questions about what they do, and to the extent that these changes incorporate or create the possibility for generative domain knowledge, they will result in self-sustaining good practices. (Contains 47 references.) (ASK)