If you can think of someone, were you thinking of your math teacher? I started thinking about teachable moments in math when I was shown this on the playground.
The student said: "I have a dollar." He had taken the original $2 coin and knocked the centre out with a hammer and screwdriver.
The picture I took after the conversation was enough of a provocation on its own. All that was needed was the question: Is it worth a dollar? If not, how much? The most likely relevant technique for coming up with an answer (area of a circle), is taught in the same grade level.
Here is the task in a tweet, with a picture made with PicCollage and Skitch:
I've been thinking a lot lately about why we have always felt the need to rely on outside sources for our math questions, problems, and tasks. Once you start to notice it, math is everywhere. This is a mindset- much like the English or Social Studies teacher has when she finds articles, texts, or news stories that relate to her tasks, lessons and units all around her. Or how about the Science teacher, who is always using the latest developments, innovations, and news as the raw materials for her lessons?
We can find authentic, meaningful and completely contextualized materials for math lessons all around us. In planning for some Ministry of education work (a webcast on proportional reasoning), I spent a few weeks ruminating on what the tasks should be. And then I went to the movies. This visual sparked 3 days of work for 3 different grade levels:
In this case I was actively hunting for materials for rates problems, but my math antennae are up these days, and they are getting good at finding the raw materials for math. Math is everywhere, and all we need is our tools like our camera rolls to record them.
The value of the toonie ring could be $1.69, but that's not accounting for the differences in the metals, or their weights.