Algebra Technology Uncategorized

Activity Builder Reflections

We’re now about 9 months into the Desmos Activity Builder Era (9 AAB – after activity-builder). It’s an exciting time to be a math teacher, and I have learned a great deal from peeling apart activities and conversing with my #MTBoS friends (run to to start peeling on your own – we’ll wait…). In the last few weeks, I have used Activities multiple times with my 9th graders.  To assess the “success” of these activities, I want to go back to 2 questions I posed in my previous post on classroom design considerations, specifically:

  • What path do I want them (students) to take to get there?
  • How does this improve upon my usual delivery?


AN INTRODUCTION TO ARITHMETIC SERIES (click here to check out the activity)

My unit or arithmetic sequences and series often became buried near the end of the year, at the mercy of “do we have time for this” and featuring weird notation and formulas which confused the kids. I never felt quite satisfied by what I was doing here.  I ripped apart my approach this year, hoping to leverage what students knew about linear functions to develop an experience which made sense. After a draft activity which still left me cold, awesome advice by Bowen Kerins and Nathan Kraft inspired some positive edits.

seatsIn the activity, students first consider seats in a theater, which leads to a review of linear function ideas. Vocabulary for arithmetic sequences is introduced, followed by a formal function for finding terms in a sequence. It’s this last piece, moving to a general rule, which worried me the most.  Was this too fast?  Was I beating kids over the head with a formula they weren’t ready for? Would the notation scare them off?

plotsThe path – having students move from a context, to prediction, to generalization, to application – was navigated cleanly by most of my students.  The important role of the common difference in building equations was evident in the conversations, and many were able to complete my final application challenge.  The next day, students were able to quickly generate functions which represent arithmetic sequences, and with less notational confusion than the past.  It certainly wasn’t all a smooth ride, but the improvement, and lack of tooth-pulling, made this a vast improvement over my previous delivery.

DID IT HIT THE HOOP? (check out the activity)

DAN.PNGDan Meyer’s “Did It Hit the Hoop” 3-act Activity probably sits on the Mount Rushmore of math goodness, and Dan’s recent share of an Activity Builder makes it all the more easy to engage your classes with this premise. In class, we are working through polynomial operations, with factoring looming large on the horizon.  My 9th graders have little experience with anything non-linear, so this seemed a perfect time to toss them into the deep end of the pool.  The students worked in partnerships, and kept track of their shot predictions with dry-erase markers on their desks. Conversations regarding parabola behavior were abundant, and I kept mental notes to work their ideas into our formal conversations the next day.  What I appreciate most about this activity is that students explore quadratic functions, but don’t need to know a lick about them to have fun with it – nor do we scare them off by demanding high-level language or intimidating equations right away.

The next day, we explored parabolas more before factoring, and developed links between standard form of a quadratic and its factored form. Specifically, what information does one form provide which the other doesn’t, and why do we care?  The path here feels less intimidating, and we always have the chance to circle back to Dan’s shots if we need to re-center discussion.  And while the jury is out on whether this improves my unit as a whole, not one person has complained about “why”…yet.


Last night, the Global Math Department hosted a well-attended webinar featuring Shelley Carranza, who is the newest Desmos Teaching Faculty member (congrats Shelley!).  It was an exciting night of sharing – if you missed it, you can replay the session on the Bigmarker GMD site.


Algebra High School Technology

Activity Builder – Classroom Design Considerations

This past summer, our forward-thinking math-teacher-centric friends at Desmos released Activity Builder into the wild, and the collective creativity of the math world has been evident as teachers work to find exciting classroom uses for the new interface. Many of these activities are now searchable at – you’re welcome to leave now and check them out – but come back…please?

Its easy to get sucked in to a new, shiny tech tool and want to jump in headfirst with a class. I’ve now created a few lessons and tried them with classes which range from the “top” in achievement, to my freshmen Algebra 1 students. In both cases, I’ve settled upon a set of guiding principles which drive how I build a lesson.

  • What do I want students to know?
  • What path do I want them to take to get there?
  • How will my lesson encourage proper usage of math vocabulary?
  • What will I do with the data I collect?
  • How does this improve upon my usual delivery?

It’s the last question which I often come back to. If making a lesson using Activity Builder (or incorporating any technology, for that matter) doesn’t improve my existing lesson, then why am I doing it?

One recent lesson I built for my algebra 1 class asked students to make discoveries regarding slopes and equations of parallel and perpendicular lines. Before I used it with my class, a quick tweet 2 days before the lesson provided a valuable peer-review from my online PLC.  It’s easy to miss the small things, and some valuable advice regarding order of slides came through, along with some mis-types. The link is provided here in the tweet if you want to play along:

The class I tried this with is not always the most persistent when it comes to math tasks, but I was mostly pleased with their effort. Certainly, the active nature of the activity trumped my usual “here are bunch of lines to draw – I sure hope they find some parallel ones” lesson.

As the class finished, I called them into a small huddle to recap what we did. This is the second lesson using Activity Builder we have done together.  In the first, the students didn’t know I can see their responses, nor understand why it might be valuable.  In this second go-round, the conversation was much deeper, and with more participation than usual. In one slide, the overlay feature allowed us to view all of our equations for lines parallel to the red line:


We could clearly see not only our class successes, but examine deeper some misunderstandings.  What’s happening with some of those non-parallel lines?  Let’s take a closer look at Kim’s work:

Parallel 2

What’s going on here? A mis-type of the slope? The students were quite helpful towards each other, and if nothing else I’m thrilled the small group conversation yielded productive ideas in a non-threatening manner – it’s OK to make errors, we just strive to move on and be great next time.  The mantra “parallel lines have the same slope” quickly became embedded.

The second half of the lesson was a little bumpier, but that’s OK.  Before questions regarding slope presented themselves in the lesson, storm clouds were evident when the activity asked students to drag a slider to build a sequence of lines perpendicular to the blue line.  Observe the collective responses:


So, before we even talk about opposite reciprocal slopes, we seem to have a conceptual misunderstanding of perpendicular lines.  I’m glad this came up during the activity and not later after much disconnected practice had taken place.  In retrospect, I wish I had put this discussion away for the day and come up with a good activity for the next day to make sure were all on board with what perpendicular lines even look like, but I pressed ahead.  We did find one student who could successfully generate a pair of perpendicular lines, and I know Alexys enjoyed her moment in the sun.


What guiding principles guide you as you build activities using technology? How do they shape what you do?  I’m eager to hear your ideas!




Activity Builder Reflections

The super-awesome Desmos folks set Activity Builder into the wild this past summer, and it’s been exciting to see the creativity gushing from my math teaching colleagues as they build activities.  So far, I have used Activities with 2 of my classes, with mixed success.

In my 9th grade Prob/Stat class, I built an Activity to assess student understanding of scatterplots and lines of best fit.  You can play along with the activity if you like: go to, and enter the code T7TP.  I am most excitied by the formative assessment opportunities an activity can provide – here are 3 places where I was able to assess class understanding.

In one slide, students were shown a scatterplot, and asked to slide a point along a number line to a “reasonable” value for the correlation coefficeient, r.  The overlay feature on the teacher dashboard allowed me to review responses with the class and consider the collective class wisdom.

r overlay

In another slide, students were again given a scatterplot and asked to set sliders for slope and y-intercept to build a best-fit line.  Again, the overlay feature was helpful, though it was also great to look at individual responses.  This led to a discussion of that pesky outlier on the right – just how much could it influence the line?

LSRL overlay

Finally, question slides were perfect for allowing students to communicate their ideas, and focus on vocabulary. In our class debrief, we discussed the meaning of slope in a best-fit line, and its role in making predictions about the overall pattern.

 question roll

But all has not been totally sunny with Activity Builder.  In my Algebra 1 class, I built an Activity to use as a station during class.  Splitting the class in half, one group worked with me on problems, while the rest worked through the activity, then flipping roles halfway through class.  You can try this activity at, code 3FGM.

Storm clouds approached early, when a student complained that they didn’t know what to do – even though the first slide offered instructions to “Drag the points…”.  Quickly my “I’m an awesome teacher who uses stations” fuzziness turned into saltiness as students clearly were not following the activity faithfully.  Here’s what I learned:

Leading class through an activity beforehand would have been helpful. In the future, I’m going to make a vanilla lesson which walks students through simple tasks – dragging points, answering questions, entering equations, adjusting sliders – and let them see how I can view and use their responses.  Just setting a class into the wild, especially a class which often struggles with instructions, didn’t work so hot.

Last Saturday, I led a group of about 20 teachers in an Activity Builder workshp at the ATMOPAV Fall Conference at Ursinus. I had 3 goals for the assembled teachers for the hour:

  • Experience activities through a student perspective.
  • Experience the teacher dashboard.
  • Start building their own activities.

Some have asked for my materials, and I can’t say I have too much to share.  Check out my Slides and feel free to contact me with questions about the hour. Some highlights of the group discussions:

  • When is the best time in a unit to use an Activity?  So far, I have used it as an intro to a unit, and also as a summary of a unit.  The difference is in the approach to task.  An intro activity should invite students to explore and play, and think about generalizations – include lots of “what do you think?” opportunities.  In my summary activity, I asked specific questions to see if students could communicate ideas based on what we had learned.
  • Think about how you will leverage to teacher dashboard to collect and view ideas.  How does the overlay feature let all students contribute and build class generalizations in a new way?  How will you highlight individual student responses to generate class conversation?
  • Ask efficient questions.  There’s really not a lot of room in the text for long-ish tasks.  Keep things short, sweet, and focused.
  • Many teachers wanted to know more about building draggable points.  The way I do this is to create a table, enter some points, and use the Edit feature to make the points draggable.  Your best bet may be to take an already existing activity and pore through its engine, which reminds me….

Desmos is now assembling an searchable archive of vetted activities.  Go to, and use the search bar at the top-left.  I highly recommend any creations by Jon Orr, Michael Fenton and Christopher Danielson.

copyAnd finally, an exciting new feature to Activity Builder just appeared today – you can now copy slides within an Activity.  Click the 3 dots to duplicate a slide and use it again, or edit a graph to use later.