Doctor Dimension Returns!

In a post a few weeks ago, I told the story of Doctor Dimension, the two-dimensional scientist who spends his fictional life filling two-dimensional containers with two-dimensional liquids, and has been doing this since 1994. In the comments, two different Bay Area math teachers directed me to Water Line, a wonderful Dan Meyer /  Desmos… Continue reading Doctor Dimension Returns!

World Cup Fever

The World Cup happens mostly during summer vacation, which is unfortunate, because it provides a great context for a geometry exploration.I start my book Geometry Labs with lessons about angles, starting from the very basics, and moving on to the inscribed angle theorem. (The book is available in its entirety as a free download here.… Continue reading World Cup Fever

Doctor Dimension

Twenty-some years ago, I started teaching an advanced high school geometry elective class called Space. I offered it every other year until I retired last year. Most of the course was about transformational geometry and symmetry. (That turned out to be excellent preparation for Common Core geometry. I will be presenting and co-presenting four workshops… Continue reading Doctor Dimension

Responses to my Common Core analysis

I have received excellent feedback about my analysis of the Common Core State Standards for high school math.E-mailed and spoken responses from my main hoped-for audience (high school math teachers) have almost without exception included a mention of having shared the paper with colleagues. For example:"I read your article about the Common Core on your… Continue reading Responses to my Common Core analysis

Completing the Square

    New animation: a geometric representation of completing the square. In this post, I present one way to use it as part of an algebra curriculum.Many secondary school teachers figure that the derivation of the quadratic formula by completing the square can be shown to students, but have little hope of any understanding. They… Continue reading Completing the Square