Category: Elementary Mathematics

Zooming in on Place Value

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 line labeled with integers is easy. Adding tenth-mark divisions to the...

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...

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 shared an Everyday Mathematics isosceles triangle investigation that...

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 bunny take 2 jumps of 4 along...

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,...

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. Oh, and did I mention that the unknowns are...

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...