Des-blog

A while back, high school teacher and Desmos fellow Sara Van Der Werf wrote about the Desmos graphing calculator in general, and the app in particular.

In the last few years I’ve started writing the phrase, “Check your solutions in Desmos.” on the bottom of any assignment that Desmos would benefit students (which is many of them).

I have found that students who do use my suggestion to use Desmos to check their work are more likely to use it on their own to check work or as a tool for exploring & learning.

Sara noticed that a much larger percentage of the students in her Minneapolis classroom had smartphones or tablets than had reliable wifi, and certainly more had these devices than had regular access to graphing calculators. So she began encouraging her students to use the school wifi to download the Desmos app, thereby ensuring they had ready access to graphing calculator technology whether online or off.

Here are some bullet points to build the case for the free Desmos app; available on both Android and iOS:

• Solving a quadratic equation? Check your answer by graphing the original function and see where it intersects the x-axis.
  
• Simplifying or factoring? Graph both forms to verify that they are equivalent.
  
• Teachers can model and support students in using the app on their phones to check themselves, reducing dependence on the teacher.
  
• Since Desmos is on the state assessments in 21 states now, the app supports students in building confidence since they learning using the same tool they will have during their assessment
  
• Once downloaded, the app does not require wifi or cellular data! The computations all happen inside your device.

The Desmos app: It’s this week’s Friday Fave!

Hashtags are funny things.

Mocked, memed, misunderstood, and yet so solidly useful.

This week’s Friday Fave is a particularly useful hashtag: #ImproveMyAB (where AB stands for Activity Builder, of course).

The brainchild of Desmos Fellow Kathy Henderson, #ImproveMyAB is a key to unlocking some most excellent collaboration online. By posting an activity to Twitter using #ImproveMyAB, you are saying two things: (1) “I have been working on an activity (or and idea for one)” and (2) “I have an inner desire to make this activity into something great!” You are issuing an invitation to conversation about teaching.

Of course, the hashtag is also a great place to stop by to see what others are making and to offer your own advice.

A quick peek at the hashtag turns up recent conversations about activities on a wide range of topics, including derivatives, exponential functions, domain and range, and exterior angles of polygons. Do you have thoughts to offer on these topics? Do you need inspiration for them? Do you have something else you’d like to work on, and need to connect with folks who can help? Check out #ImproveMyAB, it’s hashtag-amazing!

And it’s this week’s Friday Fave.

The fave is fond of triangles, and after playing with this week’s activity your students probably will be too.

This week’s fave—Exploring Triangle Area with Geoboards—is newly released and consists of a few warm up screens and a Challenge Creator. This Challenge Creator is a doozy.

How many triangles are possible on a 5-peg by 5-peg geoboard? And how many different values for the area are possible? Who knows? But whatever the number, it’s great enough to allow for a lot of creative triangle building.

Maybe you build a tricky triangle and think to yourself, “No one will be able to reproduce this one!”

But it turns reproducing your triangle isn’t the challenge; building a triangle with the same area as yours is. Indeed, odds are that your classmates will solve that challenge with a variety of triangles.

Along the way, you’ll wonder about the greatest possible area (are you sure it’s 8 square units? How do you know?), the smallest possible area (Are you sure it’s half of a square unit?), and what areas are possible in between?

The focus on student-created challenges with plenty of opportunity for creativity—that makes Exploring Triangle Area with Geoboards this week’s Friday Fave.