Three-Act Mario

I ran across Nora Oswald’s Super Mario Bros. first act on 101questions and was instantly charmed.

It puts its head down and does what my favorite first acts do: establish a context quickly, then leave a loose end hanging.

Nora Oswald wrote about the experience on her blog. Here are some choice bits:

The whole reason I created this 3-act task was to have students realize that not everything is linear. The students watched the first act and I encouraged them to make guesses, just a number from their gut. Many students used linear reasoning for their guess. I heard this over and over again today: “Since he’s a little lower than half the height of the pole, he must have a little less than half of the points.”

The model wasn’t what they expected. Oswald locates a similar flagpole model on a fan wiki. It wouldn’t be the worst idea at all to have students graph that relationship (step function!) and compare it to the incorrect linear model they anticipated.

We watch the third act (the answer). Once we are getting close to the third jump, the students are hooked, their eyes are glued to the screen, and one students rubs his palms together and says, “Here we go!”. When they see that the answer is 400, one student stands up, throws his pencil down, and complains that he was so close.

Love this also:

One of my students (who hardly says boo in class) threw his pencil down when he saw the third act. If that isn’t passion, I don’t know what is. They were in to it, they wanted to know why, they asked where those numbers came from, they made guesses, they tried to figure out why, they took pictures of the board before leaving class. One student even said that he was going to post about this on some gaming forum.

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. To see students display a positive passion toward solving a math problem brings joy to every educator’s heart. Keep up the great work!

  2. This is terrific – very simple, engaging, and transferable.
    Editing in the music across the video was an excellent choice – that music might be (perhaps sadly) the most recognizable piece of music in the world! I showed the video on my SmartBoard, turned the music on and who wouldn’t tune in then?
    So I immediately posed this lesson to my Alg 2 class. We all, of course, assumed linear, and worked like dogs to get an answer around 1300, and were shocked in act 3 that it wasn’t even close.

    BAM! Not everything’s linear!

    That was our introduction to quadratics.