Des-blog

by Christopher

This summer, we launched Activity Builder—a tool for teachers to use to build Desmos-based lessons to use in their classrooms. The community of online math (and other!) teachers has been tremendously creative in response.

We wanted to make this creativity available to a wider audience, so we recently introduced search on teacher.desmos.com.

In order to make search maximally useful, we have engaged in a curation process we call polishing. Basically, we go through every Activity Builder activity that teachers create, look to see whether they have agreed to share these activities, and then edit them before making them searchable. Polishing involves proofreading, applying stylistic touches for consistency, and adding or rearranging screens.

Some activities get a light touch; others undergo substantial changes. We check in with the original authors to be sure they are still happy to have their names on the final product before we release it. (Also Jenny makes it a really sweet logo!)

From time to time we’ll feature an activity and what we find interesting or useful about each one.

Today, I’ll tell you about a tiny little activity from David Cox.

Where’s 2/3? is not going to consume an entire class period in anybody’s classroom. But its simple structure is delightful. If you want to learn to use words effectively, study Maurice Sendak. If you want to learn to use tech effectively, study the simple things.

Here’s the structure.

1. Question: How does 2/3 relate to 1?

2. Do it: Put 2/3 on the number line.

3. Reflection question: How did you know where to put it?

Engage kids’ minds with a simple question that sets up the next thing, but that has low stakes. Have them do a thing with a simple tool. Ask them to justify.

In polishing, I experimented with a new interaction. David’s original lesson has the red dot pinned to the number line. I wanted to provide a couple of reference points for students to use (maybe they want to subdivide into thirds first?)

Putting multiple dots on the number line was confusing, so I put them above the number line for kids to place like stickers. A little hocus pocus makes it so those points are easy to put ON the number line.

Maybe you like the pinned-points better? No problem! You can make that version for yourself in about four minutes**. And you’ll learn a couple things along the way. (Also, soon you’ll be able to make a copy of an existing activity and edit it, rather than start from scratch. Very soon. But not today.)

The hocus pocus is simply setting limits on the sliders. Click the triangle next to the word “Use” in the expressions list to see the draggable-point mechanics.

**Or hit me on Twitter—@Trianglemancsd. I’ll build it for you!

Counting large numbers of little things is tedious work.

Sixth graders know there has to be a better way—one that is faster and more efficient. They don’t always know that algebra is that better way; a gateway to a new set of methods. They almost certainly don’t know that proportional relationships are a key that unlocks that algebra gate.

That’s why we built Tile Pile in collaboration with partners Illustrative Mathematics and Smarter Balanced Assessment Consortium. Tile Pile challenges students to calculate the number of tiles needed to tile a large floor, and gives students a powerful mathematical tool—a ratio table—for doing these calculations.

Hey Sixth-Grader! we say. You found the number of tiles in 4 square feet. How many in 20 square feet? How do you know?

And then we don’t let them rest on their laurels. We make them think about how other students got their answers. Because collaboration, that’s why!

Possibilities include (but may not be limited to):

• Multiply the number of tiles in 4 square feet by 5.
• Add the number of tiles in four square feet to the number of tiles in sixteen square feet.
  
• Multiply 20 by the number of tiles in one square foot (the unit rate!)

Ideas, like seeds, are planted. Then, like seeds, these ideas grow in the fertile ground of the (approx.) 11-year-old mind. Students reason their way to a total number of tiles. They fix Lusenia’s table. They learn about the constant of proportionality.

Then students put their feet up, take a long drink of cool water, get the thumbs-up from their coworkers and enjoy the satisfaction of a job well done.

Good work, sixth-graders! We’ll see you in seventh grade when y=kx rolls around.

So teachers, what are you waiting for? That floor won’t tile itself. Click on through and try Tile Pile out now.

What will you build today?

At Desmos, we hope you’ll build an awesome online lesson that will engage, challenge, and enlighten your students. So really, we hope you’ll build young minds.

Activity Builder is a tool for helping you do just that. Whether you build something simple like a check for understanding to use in the middle of your lesson (Everybody graph a parabola with the vertex at (1,1)!) or a multi-step activity with multiple interactive graphs and rich questions, Activity Builder allows you and your students to move beyond the constraints of the paper handout.

You can see your students’ graphs on your dashboard—either individually or collectively—while they’re working. You can see students’ answers to the questions you ask and keep track of their progress through the activity.

Click on through to see how it works and get building.

See Match My Line and Match My Parabola for examples that you can use in your own classroom. Hopefully they’ll inspire you to build your own and share your creation with the world.