In addition to my blog on WordPress (this site) I maintain a huge math education site, featuring articles about teaching math and tons of curricular materials. You should definitely check it out. I keep track of updates to the site on this page.
Applets: I restored many GeoGebra files which could not be opened by recent versions of the software. I think I got all of them, but let me know if I missed some!
Summer Workshop: This is the page about Hands-On Geometry, my 2020 summer workshop for middle school teachers. It will be hosted by Atrium School near Boston, July 21-23 and Synapse School in Silicon Valley, Aug 4-7.
Make your own Pentominoes: I added a laser cutter file (made by Eben LaPier) to my site. You can download it from my Geometric Puzzles page, where I explain why laser-cut pentominoes are preferable to the commercially available ones. The same page, of course, links to lots of puzzles for the classroom.
Fraction Arithmetic on Grid Paper: I drastically expanded this page, adding details, graphics, and five homemade videos. One big idea, with many uses across that domain.
Left or Right?: I tweaked and linked to this activity which can serve as review or assessment of understanding of y = mx + b. Answer without actually graphing: given these two linear functions, do the lines meet to the left or to the right of the y-axis?
Off and On / Add Till It’s Plaid: Two lessons that illustrate ax + by = c through possibly unfamiliar activities: what does ax + by add up to for a generic point (x,y) somewhere in the plane? what happens visually when we add or subtract a pair of equations in this form? I used video to present the core of the lessons. I also added an Off and On applet so you and your students can conduct that experiment using an equation of your choice.
Stairs: This is a beginner’s “rise over run” activity which I designed ages ago for TI calculators. Later, I attempted a Desmos version, which (perhaps due to my lack of expertise) had various issues. I replaced it with a GeoGebra applet, something I knew how to make.
Number Pyramids: I added a puzzle-solving and puzzle-creating activity for upper elementary and middle school, mostly based on the addition of whole numbers.
Geometry of the Parabola, 2D: I added a paragraph (by Rachel Chou). Yet another argument to convince the reader that all parabolas have exactly the same shape. They cannot be “pointier” or “wider”.
Talks: I added information on the free professional development session Lessons from Lew, as well as links to an expanded version of the handouts.
Iterating Functions: This page includes interesting materials on this topic, ranging from pre-algebra to precalculus. I added a new lesson by Rachel Chou, about an unexpected application of these ideas to geometry: Triangles and Iterations.
Doctor Dimension: This is a small unit with big ideas mostly about rate of change, including several GeoGebra applets and a selection of worksheets. It can be used in different ways, in grades 8-12. I added a link to another lesson about piecewise functions.
Stairs: This is a Desmos-powered applet that can be used to explore “rise and run”. Unfortunately, it doesn’t work in Chrome on Windows. I added a note to that effect.
Puzzles in Math Curriculum: I combined a couple of blog posts into an article where I break down what makes a good puzzle, and more specifically, what makes a good puzzle in math class.
Letters and Postcards: This is an introduction to linear inequalities and “linear programming.” I added a link to Liz Caffrey’s Desmos Activity Builder version of the lesson.
Stairs: I added a worksheet to support this Desmos-powered applet about slope and linear functions. (Unfortunately, the applet doesn’t seem to work on Chrome on a PC. I’ll try to fix it, but until I do, try a different browser.)
Staircases: I made minor tweaks to this worksheet, which is a great activity about adding up strings of consecutive numbers. It works at all levels from 4th grade, to high school, to math teacher!
Name That Function! This is a popular GeoGebra applet where you’re supposed to guess the function by watching an animated function diagram. I added links to worksheet versions of it, which can be used instead or in addition to the applet.
Summer Workshops: This is the page about my 2019 summer workshop: Visual Algebra (grades 6-9), in two locations: June in Silicon Valley, August near Boston. I added a link to the participants’ website. I also added mentions of continuing education / graduate school units, the 75% scholarship for public school teachers, and the free and discounted manipulatives from Didax and Nasco.
Symmetric Polygons: I corrected a mathematical error and expanded the teachers’ notes in this activity for grades 8-10. Co-authored with Lew Douglas.
Seems Isosceles!: I added some interactive GeoGebra images to this “teachers’ mathematics” exploration.
Geometry Labs: minor tweaks.
For a Tool-Rich Pedagogy: This page consists of an argument for the use of manipulative, technological, and paper-pencil tools in math education, followed by a long (but probably incomplete) list of links to related pages on my site. I added a link to my popular page about pattern block dodecagons.
Pythagorean Theorem home page: I added an image.
Geoboard home page: I added “Connect the Dots” — lattice puzzles and problems for teachers, which can also be used in math clubs and in the classroom. (We worked on those at Math Teachers’ Circles.)
Summer Workshops: I set up that page to announce my 2019 summer workshop: Visual Algebra (grades 6-9), in two locations: June in Silicon Valley, August near Boston.
Soccer Angles: I added interactive GeoGebra applets to this page, which is an extension of the low-tech Lab with the same name in Geometry Labs.
Spirograph Simulation: For some reason, while the online applet worked, the GeoGebra file I included did not open when downloaded. I got some help on Twitter, and posted a corrected version.
Math Ed Consulting: minor tweaks.
Electronic Graphing: minor tweaks.
Pattern Blocks: I added a link to Jen Silverman’s GeoGebra pattern blocks applet.
I created a conic sections home page. (Links to the geometry of the parabola and ellipse, 2D and 3D, and more.)