Archive for February 2011
Why does a triangle have an area?
Posted by: Gary Ernest Davis on: February 23, 2011
In a lovely series of videos James Tanton clarifies the formula for the area of a plane triangle. Starting from some simple postulates, namely: area is additive over finitely many parts that do not overlap; congruent figures have equal area; a rectangle of length and width has area James shows that, if a triangle has […]
A challenge to mathematics teachers: can your class become a community of practice?
Posted by: Gary Ernest Davis on: February 23, 2011
Jean Lave and Etienne Wenger wrote an influential book: Situated Learning: Legitimate Peripheral Participation (Learning in Doing: Social, Cognitive and Computational Perspectives). As a budding mathematics educator this book had a big influence on me and, over the years since first reading it, I have often reflected how different a typical mathematics classroomĂ‚Â is from […]
