The Return of the Odometer

In my prior post, I presented an interactive Web Sketchpad odometer that is a great tool for introducing young learners to place value. Well, technology moves fast these days, and the latest odometers are more powerful than ever. While our prior odometer featured '+' buttons above each digit, our newest innovation in number-tracking technology features  '+' and … Continue Reading ››

Soccer Challenges: Angling for a Shot on Goal

With the World Cup in our hemisphere, and the US squad having started out with a win over Ghana, my thoughts turned to the mathematics of soccer. My friend Henri Picciotto has a nice page about the shooting angle, the angle within which a shot is on goal, so I thought of using … Continue Reading ››

Questioning Some Dynamic Geometry Angle Wisdom

For the past eight months, my colleague Scott Steketee and I have collaborated with the authors of the elementary curriculum Everyday Mathematics to design interactive Web Sketchpad models for their next edition. When it came time to create a Sketchpad representation of an isosceles triangle, I built the interactive triangle model below. Try dragging any of … Continue Reading ››

Create Parametric Curves Graphically and Kinesthetically

In this guest post, Nate Burchell describes a sketch he uses with his students to explore parametric functions. In this process students work entirely in a graphical world, manipulating graphs directly rather than by way of equations. (Nate teaches in Seoul, Korea, where I enjoyed his family's hospitality when I attended ICME in … Continue Reading ››

A Funhouse Mirror of Sketchpad Transformations

Did you know that The Geometer's Sketchpad is a great tool for creating funhouse mirror pictures? Sure, Sketchpad can reflect, rotate, translate, or dilate a picture, but these operations are rather tame: They transform images uniformly, producing pictures that are easily recognizable versions of the original. By contrast, Sketchpad's "custom transform" feature allows you to apply non-linear transformations … Continue Reading ››

Sketchpad Explorer Featured in Mathematics Teacher

The May issue of Mathematics Teacher (MT) has a Technology Tips article on High-Leverage iPad Apps for the Mathematics Classroom by Ayanna Perry, Emily Thrasher, and HollyLynne Lee of North Carolina State University. They explain how to transfer files to student tablets, and they make a number of recommendations … Continue Reading ››

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