One of the aspects I like best about Dynamic Geometry software like Web Sketchpad is its ability to illustrate concepts that cannot effectively be represented with static media. Take, for example, a number line that we draw on a white board. Showing the number … Continue Reading ››
Category Archives: Elementary Mathematics
Exploring Triangle Area with Custom-Built Tools
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 … Continue Reading ››
Around and Around: Investigating Multiples
In my prior posts ( When Factoring Gets Personal, Open the Safe, and Reasoning with Multiples to Find the Mystery Number), I’ve given examples of how learning about multiples and factors … Continue Reading ››
Solving Simultaneous Equations with Common Sense
Simultaneous equations belong in elementary-school mathematics curricula. That's been my mantra for many years, and I want to examine it now in the context of an interactive Web Sketchpad activity.
When I say that elementary-age students should encounter simultaneous equations, I don't mean that they should be instructed in the standard algebraic procedure for solving pairs of equations … Continue Reading ››
Moving Beyond Formulas When Investigating Triangle Area
For the past year, my blogging partner Scott and I have worked with the team of Everyday Mathematics to build interactive Web Sketchpad models for their forthcoming new edition. It's been fun for both of us to find ways to insert dynamic mathematics into their K–6 curriculum. Last year, I … Continue Reading ››
Exploring Factor Rainbows
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 (and here), press Jump Along to watch the … Continue Reading ››
Isosceles Triangle Puzzles
As readers of this blog can probably tell, I like puzzles. I especially enjoy taking ordinary mathematical topics that might not seem puzzle worthy and finding ways to inject some challenge, excitement, and mystery into them.
This week, I set my sights on isosceles triangles. It's common to encounter isosceles triangles as supporting players in geometric proofs, but … Continue Reading ››
Dancing Unknowns: You Haven’t Seen Simultaneous Equations Like These!
When it comes to simultaneous equations, I like to push the bounds of conventional pedagogical wisdom. In an earlier post, I offered a puzzle in which elementary-age students solve for four unknowns given eight equations. Now, I'd like to present a puzzle that might sound even more audacious: Solving for ten unknowns. … Continue Reading ››
A Balance Model Approach to Algebraic Equations
From 2009 to 2013, I had the pleasure of working with the elementary teachers at the School for Discovery and Exploration in Brooklyn, New York as they field tested Sketchpad materials for the Dynamic Number project.
Although the project has … Continue Reading ››
Logic Puzzles Made Visual
When I was child, I loved to solve the brainteasers in logic puzzle magazines. You probably know the type:
Ruth, Phyllis, and Joan each bought a different kind of fruit (orange, apple, pear) and a different vegetable (spinach, kale, carrots) at the supermarket. No one bought both an orange and carrots. Ruth didn't buy an apple or kale. … Continue Reading ››