R2D2 Post-Its by @MrOrr_geek 3 Act Math Task Summary

Applying Area to Proportional Reasoning

R2D2 Post-Its 3 Act Math Task by Jon Orr - Area and Proportional Reasoning

Thus far in the spiral, I haven’t made it to measurement yet. Today, we’re going to touch on area and lead us into an exploration of area formulas over the next day or so. Jon Orr’s R2D2 Post-It Notes 3 Act Math Challenge is a nice low floor task that works with area of a rectangle and proportional reasoning. Here’s the Act 1 video we show the students:

Can’t see the video? Click here.

Here’s the question we eventually settle on:

Determine how many post-it notes it will take to cover the board?

My students came up with some predictions including:

  • Alex – 888
  • Jaden – 700
  • Olivia – 688
  • Cole – 756
  • Grace – 900
  • Lowwwwza – 950
  • Stef – 800
  • Vanessa V – 820
  • Tristan – 600

After making some predictions, students requested information. Here’s what I gave them:

Week in Review #2 - R2D2 - Act 2 - DimensionsPost-It

Week in Review #2 - R2D2 - Act 2 - Dimensions Board

At this point, I also gave them a math task template to help organize their thoughts and consolidate their learning once we took up the task:

Week In Review #2 - R2D2 Post Its - Math Task Template Screenshot

Then, students were off to town.

Here’s a few student exemplars I saw walking around the room:

Week In Review #2 - R2D2 Post Its - Student Exemplar 3

Week In Review #2 - R2D2 Post Its - Student Exemplar 2

Week In Review #2 - R2D2 Post Its - Student Exemplar 1

Act 3 – Revealing the Solution

Now, students can check there answers against what really happened:

Can’t see the video? Click here.

If you don’t think these sorts of tasks can make math fun, these kids are going to prove you wrong:


After showing the solution, students worked on the second page of the template and we consolidated our new knowledge. Notice that I am scaffolding students to start naming the variables as independent/dependent, labelling them on the table and graph, and also adding their own scale to the graph.

We also introduce a simple one-step (proportional) linear equation that students must create and solve for the independent variable. First time we’ve done that this year.

Jon also created a Gameshow related to this task, so here it is:

Note that you can embed this gameshow on your own website/LMS/blog/etc. by simply copying the embed code that Gameshow gives you inside of your teacher account.

Conveniently, this task and all media files are available for download to your iOS device from iTunes U in the Curious Math course. I ran this task straight from my iPad using the files in the course. The benefit is that the files download to your device so you aren’t stuck with any streaming issues if traffic on your network is high.

You can enrol in the course below:

Curious Math Foundations of Mathematics MFM1P iTunes U Course Cover

Enrol in Course

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