A challenge for educational employing authorities is the provision of high-quality, sustainable professional development opportunities that will lead to positive growth in teachers' pedagogical practices. The study reported here sought to devise and implement a model of teacher professional development that would result in such growth by…

Learning about the area formulas provides many opportunities for students even at the beginning of junior secondary school to experience mathematical deduction. For example, in easy cases, students can put two triangles together to make a rectangle, and so deduce that the area of a triangle is half the area of a corresponding rectangle. They can…