Geometric Puzzles at Asilomar

I'll be presenting a session on Geometric Puzzles at the Asilomar meeting of the California Math Council. (Saturday, Dec 2, Sanderling, 1:30pm The printed program says I'm in the middle school, but that is not correct. The app has the location right.). I will include material that I believe is relevant to teachers from kindergarten… Continue reading Geometric Puzzles at Asilomar

Puzzles for the Classroom

In my last post, I shared some generalities about puzzle creation. Today, I will zero in on the specifics of creating puzzles for the mathematics classroom. I will do this by way of analyzing some examples. Multiple PathsA characteristic of all classrooms is that they are constituted of students whose backgrounds and talents vary widely. … Continue reading Puzzles for the Classroom

Transformational Proof

Prior to the publication of the Common Core State Standards for Math (CCSSM), transformational geometry was rarely seen in geometry courses. It certainly was missing from the one I taught. Still, I have always been interested in this topic, and it provided the backbone of my "Geometry 2" class, a post-Algebra 2 elective which I… Continue reading Transformational Proof

More on Geometric Construction

(To search from previous posts on this topic, use the Search box on the right.) I suspect that by far the most common introduction to geometric construction in US classrooms is a presentation by the teacher (or textbook) on various compass and straightedge construction techniques. "This is how you construct a perpendicular bisector. This is… Continue reading More on Geometric Construction

Errata

According to Merriam-Webster, the word errata means "errors" in Latin, but it is used in English to mean corrigenda which in Latin means "corrections". So there you have it: errors can be corrected — student errors, teacher errors, and (ahem) curriculum developer errors.My books, great as they are, do contain errors. Some are small errors… Continue reading Errata

Geoboard Problems for Teachers

At the San Francisco Math Teachers' Circle yesterday (March 4, 2017), we explored four "teacher-level" geoboard problems (All can be adapted for classroom use.) Here is a brief report, including some spoilers, I'm afraid. Pick's Formula It turns out that the area of a geoboard polygon can be figured out by counting the lattice points… Continue reading Geoboard Problems for Teachers

Time and Tide

This is my yearly report on the Asilomar conference of the California Math Council, Northern Section. Because I was presenting three times, I didn't end up attending as many sessions as I would have liked. As always at Asilomar, I enjoyed hanging out with my ex-colleagues, running into friends, and meeting the occasional fan of… Continue reading Time and Tide