Make These Designs

Among the activities I have developed, "Make These Designs" is among the most popular. Students enjoy it, and teachers appreciate how it can be used as an engaging introduction to, or interesting review of, an important topic: graphs of linear functions, and the parameters m and b in y=mx+b.When electronic graphing first came onto the… Continue reading Make These Designs

Proportional Relationships

One good thing about the Common Core middle school standards is the emphasis on proportional relationships, and the fact that they are approached in a multidimensional way. In addition to "set up a proportion and solve it", which is probably the most common way to teach this, the standards propose multiple representations and a variety… Continue reading Proportional Relationships

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

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