Many of the approaches to mathematics professional development gaining prominence over the past decade have at their core a common guiding premise about teacher change: that good mathematics teaching begins with understanding how mathematics is learned. In various ways they create experiences which invite teachers to be attentive to-and curious about-students' mathematical ideas.

Often, these approaches also invite teachers to adopt an inquiring stance toward their own mathematical understanding, but the core of the premise holds that a consistent focus on student mathematical thinking will open teachers to new and more effective ways to promote students' further mathematical knowledge and understanding.