As you may remember from my previous posts on this subject, I have been thinking a lot about the Common Core approach to secondary-school geometry, specifically the logical switcheroo that makes triangle congruence and similarity a consequence of assumptions about geometric transformations, rather than the other way around. To support this change, I have started… Continue reading Triangle Similarity Update

# Tag: Common Core

## Rethinking Triangle Congruence and Similarity

As you may know, I have discussed transformational geometry and the Common Core State Standards for Math (CCSSM) several times on this blog. This summer, I have already been a presenter in two professional development workshops on transformational geometry, and will be involved in two more. This has pushed me to move forward on writing… Continue reading Rethinking Triangle Congruence and Similarity

## 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

## More Algebra Book Fan Mail

I have some good news for the users of the online version of Algebra: Themes, Tools, Concepts (ATTC, the textbook I co-authored with Anita Wah): all the ATTC PDFs are now searchable, and many of the files are smaller than they used to be. (See below for links.)Amanda Cangelosi, a Mathematics instructor at the University… Continue reading More Algebra Book Fan Mail

## Middle School

I have taught grades K-5, high school, future teachers, and working teachers, but I have never taught middle school, except for a couple of summer jobs some years ago. Nevertheless, my curriculum materials are widely used at that level, and maybe half the teachers I have worked with are middle school teachers.I just started a… Continue reading Middle School

## The Common Core

Now that I'm a freelance math education consultant and curriculum developer, I need to pay attention to the Common Core State Standards as they affect everything I do in my professional life. Merely listening to talks about the standards, and reading angry posts about them did not provide a lot of information. On the other… Continue reading The Common Core

## Algebra: Themes, Tools, Concepts and the Common Core

Way back in the early 90's, I co-authored the textbook Algebra: Themes, Tools, Concepts (ATTC) with Anita Wah. It failed to become a best-seller, in part because while the lessons work well with students, the book is not very easy for teachers to manage. Still it's a good book. We have continued to use different… Continue reading Algebra: Themes, Tools, Concepts and the Common Core

## New Transformational Geometry Page

I've added a Transformational Geometry page to my Web site. I expect it will grow over the next year, as I get further into this and develop new ideas and materials. (See also my earlier post on transformational geometry, which generated an interesting response.) --Henri

## "A New Algebra"

About twenty years ago, along with Anita Wah, I wrote "A New Algebra", a paper for the Journal of Mathematical Behavior (JMB). It was an attempt to address what I saw as a crucial issue in secondary math education: on the one hand, the traditional Algebra 1 course was the gateway to any further work… Continue reading "A New Algebra"

## Transformational Geometry, cont’d.

As I mentioned in a recent post, I will be one of the presenters at the Bay Area Math Project's summer workshop on Transformational Geometry. As part of preparing for this, I went through my notes, and compiled a sort of syllabus of the relevant lessons from my Space course. Symmetry and transformations are the… Continue reading Transformational Geometry, cont’d.