My Favourite Resources: Dan Meyer’s 3 Act Math

At the moment both me and the colleague I joint plan with have ITE students teaching our Year 10 top sets for 3 out of 4 contacts a week. In the remaining lesson we’re teaching them a mixture of geeky enrichment and Level 2 Further Maths. I’ve been wanting to try some of Dan Meyer’s 3 Acts activities for a long time so a few weeks ago we dived in with both feet and gave one a go. My class loved it and left asking “can we do another activity like that, Miss” and “that’s proper Maths that is!”  


What I think amazes me is, I expected these task to be problem solving, real-life activities that made pupils think, discuss and develop good key Mathematical skills but I completely underestimated the total buzz of Mathematics they would create and how rich and rewarding the ensuing discussions would be. 

Below I’ve given a little commentary on the two tasks we’ve tried. My colleague, Emma, has also kindly agreed that we will share our lesson outline PowerPoints in case any of you want to take them and run with them. In most cases we’ve added to and enriched the awesome work that is already on Dan’s site to better suit the individual needs of our classes and curriculum. 

One thing to be aware of is that these lessons will go off on a tangent so be ready to go with the flow but an enthused, buzzing classroom is always a wonderful place to be. 

I genuinely cannot wait to do more of these; I wish I hadn’t waited so long to give one a shot. You can find all Dan’s tasks here, follow Dan on Twitter here and subscribe to Dan’s blog here. You should probably do all three. Right now. 

Task: Water Tank

Skills used: area, volume, estimation, unit conversion, time conversion (some used Pythagoras, trig or sine and cosine rule to find area of hexagon), percentage error

On the face of it this seems like a pretty dull scenario; estimate the time it will take to fill and then empty a container. Pupils used various different methods for finding the area of the hexagonal cross-section which I’ve tried to capture in the photos below. After showing the act one video I gave them time to decide what information they wanted from me. If they asked that after the thinking time they were given it but if they didn’t ask for it at that point they couldn’t have it (they actually asked for all 5 key pieces of information as a class so got some good estimates in the end.)


I was extra impressed with the eager eyed team who spotted that there may actually be a cylindrical inner container and their estimate was pretty close in the end! 

The added element of competition added to the enthusiasm and desire for accuracy. 


You can access our PowerPoint resource for Water Tank here

Task: Super Bear

Skills used: estimation, volume scale factors, conversion of units, value for money, percentage error.  

Again looks like a simple task but incredibly rich. And, hell, that bear is cuuuute. We let the estimation phase run for a while (I instigated a discussion about volume scale factors here too by writing the statement “If I double the lengths I double the volume” on the board) before releasing the mass details. We’ve added to it by adding in some value for money and percentage error work which both led to nice discussions. In the former some went for pence per gram, others for grams per pound. Did it matter? “What would be different in these two methods and how you reach your conclusion from your results?” The latter was a really nice discussion of what large percentage errors mean and what the value actually means. 


Again I added a competitive element. 


You can access our PowerPoint resource for Super Bear here


  1. Thom H Gibson · April 24, 2015

    I recently did my first 3 Act Problem and the kids loved it (the caffeine concentration one). I like the idea of not giving them the information if they don’t ask for it. I ended up using Act 3 as a question on their unit exam we had later on.

    How did you involve competition? See who got the closest? Do you give them the final right answer?

    • ideasfortheclassroom · April 24, 2015

      Hi Thom. I haven’t looked at the caffeine problem in depth yet so will seek it out. Yes it was about closest although there was no reward apart from pride! My students know that any rewards in my classroom are for effort rather than outcome so I’ll give actual rewards/ praise for teamwork skills.

    • ideasfortheclassroom · May 4, 2015

      Hi Thom. Yes we did who got the closest. I also rewarded the best teamwork. We watched the right answer videos in both instances 🙂

      • Thom H Gibson · May 4, 2015

        Ah, I haven’t run into a 3-Act-Problem that has a ‘right answer’ video yet. That makes sense 🙂

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