Today, another guest post, this time from a homeschooling mom. -- Henri Algebra and Geometry Greetings! I hope this email finds you well. I know you don’t know us, but I wanted to personally thank you for your math books. I cannot express how helpful your books have been, and the relief I have… Continue reading Letter from a Homeschooling Mom
Tag: Geometry
Proof in High School
Proof in Geometry Many years ago, when I was still teaching high school, I added a Teaching Proof page to my website, which included a bit of philosophizing and links to the relevant parts of the site. If you’re looking for ideas and materials on this topic, you should definitely check out that page. I’ve… Continue reading Proof in High School
Working with Pentominoes
This is an update of a post from 2013, when Didax published my book Working with Pentominoes. You can still buy the book. It is geared to grades 4-8, though I used some of the content in high school. Pentominoes are a geometric puzzle, a staple of recreational mathematics. This is what they look like:… Continue reading Working with Pentominoes
Tangram Puzzles
When I was a beginning K-5 teacher in the 1970’s, my father-in-law introduced me to pentominoes. It was clear to me that there had to be some way to incorporate those in my teaching. It wasn’t long before I instituted a weekly "math lab" session for my students: every Friday, they had an opportunity to… Continue reading Tangram Puzzles
The Three Triangles
I recently added a guided inquiry worksheet on my website’s Pythagorean theorem page. It leads students along a proof of the theorem based on similarity. It is called The Three Triangles. This is a worksheet I used and honed over the years when I taught geometry. Upon rereading it, I thought it would make a… Continue reading The Three Triangles
Another Use for the Lab Gear
I am the creator of the Lab Gear, a manipulative environment for learning algebra. It is more expensive than the better-known algebra tiles, in their various versions, but it is much more effective in the classroom. At least that is the opinion of those teachers I know who have used both. As one of them… Continue reading Another Use for the Lab Gear
A Construction Unit
I have written about geometric construction a number of times on this blog, and on my website. I outlined my philosophical outlook on this topic here. Today I summarize some construction activities, a subset of the unit you can find on my website. —————————————————————————————————— Geometric construction with straightedge and compass is a standard topic in… Continue reading A Construction Unit
Geometry Labs Notes
In this post, I share thoughts about my Geometry Labs (free download), and complement some of Mimi Yang's notes about it. (In fact, this post was suggested by the existence of Mimi’s notes. You may find those useful, as she lists which topics are supported by various labs.) First, big-picture thoughts. The book includes obviously… Continue reading Geometry Labs Notes
Matrices
As a high school teacher, my first attempts at teaching about matrices were not successful. I tried to sell them as a way to solve systems of linear equations with three or more unknowns. This was a highly technical approach to something my students were not particularly interested in. It was not a hit, and… Continue reading Matrices
Supertangrams
Many years ago, in the exhibits area at an NCTM national meeting (in New Orleans?), I saw math teachers standing in an insanely long line. I had never seen anything like it, and never saw anything like it since. They were waiting to have a book signed by Martin Gardner, the author of the “Mathematical… Continue reading Supertangrams
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