Many, many years ago, I saw this problem somewhere: Arrange the whole numbers from 1 to 18 into nine pairs, so that the sum of the numbers in each pair is a perfect square. I liked the problem, and included it in a book I co-authored (Algebra: Themes, Tools, Concepts, following lesson 5.5). In the… Continue reading I’ve Got a Problem!
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Pattern Blocks
Geometry of the Parabola
Parabolas are a central topic in high school algebra classes, but, perhaps because of the rigid separation between algebra and geometry classes in the US secondary curriculum, we do not usually treat them as geometric objects. While most teachers are aware of some of the parabola's geometric properties, few of us are familiar with the… Continue reading Geometry of the Parabola
Pie are square
Just in time for π day, I posted an animation that tries to show that the formula for the area of a circle is plausible. Check it out here. It is almost a proof that pie are square!--Henri
Pattern Blocks on Pi Day
I'll be offering a workshop for middle school and high school teachers on March 14 at the American Institute for Mathematics in San Jose. My topic is pattern blocks:<img alt="" height="76" src="data: Pattern blocks are ubiquitous in elementary schools, but they're not commonly seen in middle school or high school. Yet, they do offer plenty of… Continue reading Pattern Blocks on Pi Day
Math for Equity
A couple of years ago, I recommended a few books on complex instruction, an approach to teaching that was refined by a group of teachers in a Bay Area public school nicknamed "Railside", as it sits "on the wrong side of the tracks." My recommendation was based not on reading the books, but on my… Continue reading Math for Equity
Summer Workshops, 2015
I'll be teaching four workshops this summer, in two new locations: Seattle, and Waltham, MA (which is a half-hour West of Boston.) If you've meant to attend my workshops in the past, but couldn't make it to San Francisco, New York, or DC, perhaps these venues are more convenient for you? There will be no… Continue reading Summer Workshops, 2015
Geometric Construction, continued
Readers of this blog probably realize that I'm very much into geometric construction. This is in part related to my general interest in puzzles, in and out of the classroom. (In my other life, I construct cryptic crosswords.) My first math education publications were books of geometric puzzles for grades K-10. My pentomino puzzle books stayed… Continue reading Geometric Construction, continued
Asilomar Report: Think First
I attended the California Math Council meeting last Saturday. This post is a report on one talk I attended. It was given by Scott Farrand, a prof at Cal State University Sacramento. (I also reported on one of his talks last year.)This year's talk was called "Think First", which can be interpreted a few ways,… Continue reading Asilomar Report: Think First
One More Pythagorean Proof
I added a third dynamic proof of the Pythagorean theorem on my Web site. It is better-looking, but more difficult to justify than the previous two. You can see all three, starting here. For a brief discussion of how you might use these in the classroom, see this post. --Henri
Henri's Math Education Blog 