Where Mathematics Content Knowledge Matters: Learning About and Building on Children's Mathematical Thinking
The importance of teachers' knowledge of content is currently a prominent issue in calls for education reform in the United States. Although there is widespread belief in the importance of teachers' content knowledge, it is not clear how such knowledge plays out in instruction. This lack of clarity is due, in part, to the complexity of teaching and, in part, to the complexity of teachers' cognition in general and their specific knowledge. It is, for example, impossible to separate teachers' knowledge from their beliefs (Fennema & Franke, 1992; Thompson, 1992). Further, "Common sense suggests that teacher knowledge is not monolithic. It is a large, integrated, functioning system with each part difficult to isolate" (Fennema & Franke, 1992, p. 149). This makes it difficult to know how specific types of knowledge influence teaching.