*Everyday Mathematics*. My goal was to design a lesson focusing on the triangle area formula,

*A*=

*bh*/2. … Continue Reading ››

With Web Sketchpad, it's easy to craft tools that are tailor made for the task at hand. I was reminded of this flexibility several weeks ago when creating an interactive model for the elementary curriculum *Everyday Mathematics*.
My goal was to design a lesson focusing on the triangle area formula, *A* = *bh*/2. … Continue Reading ››

The origins of this week's Web Sketchpad model date back to the Connected Geometry curriculum from the mid 1990s. I was one of the co-authors of the curriculum, working at Education Development Center with a wonderful team of math educators (Al Cuoco, Paul … Continue Reading ››

This Thursday, Scott Steketee and I will be presenting two sessions at the NCTM 2015 Annual Meting in Boston:
**Functions as Dances: Experience Variation and Relative Rate of Change**

Session 52 on Thursday, April 16, 2015: 8:00 AM-9:15 AM in 157 B/C (BCEC)

How better to explore rate of change than as independent and … Continue Reading ››

For this year’s Pi Day post, I thought I’d continue our Web Sketchpad (WSP) construction theme. But rather than adapting the visualizations from last year’s Pi Day post to the new construction capabilities, I decided to take a different approach. Some time ago, I built a set of custom tools for … Continue Reading ››

Dan Meyer has posted a number of "What Can You Do With This?" activities on his blog. (Activities is probably too prescriptive a word; they're more in the nature of prompts for student thinking, noticing, and wondering.) One of the first was the image below, which he made by superimposing frames from a … Continue Reading ››

In my prior blog posts, I've described how to construct ellipses using linkages, concentric circles, congruent triangles, and tangent circles. These are all great methods, but I think I got ahead of myself: There's a simple ellipse … Continue Reading ››

For the past month, I've focused this blog on the role that computers can play in assessing students' mathematical knowledge. I've presented three Web Sketchpad-based examples of assessment with mathematical topics ranging from isosceles triangles, to the Pythagorean Theorem, to the Continue Reading ››

This week, I'm going to describe one of my favorite activities for introducing young learners to multiplication and factors. It comes from Nathalie Sinclair, a professor of mathematics education at Simon Fraser University.
In the interactive Web Sketchpad model below, press *Jump Along* to watch the bunny take 2 jumps of 4 … Continue Reading ››

The 17th-century Dutch mathematician Frans van Schooten developed "hands-on manipulatives" centuries before the term became popular in math education circles. Below are two images of ellipse-drawing linkages from van Schooten's manuscript, *Sive de Organica Conicarum Sectionum in Plano Descriptione, Tractatus* (*A Treatise on De**vic**es for Drawing Conic Sections*).
Continue Reading ››