Order All The Pizzas!

In Dan Meyer’s recent talk at NCTM, he shared some contrived examples of “real world” math, including this one about congruent triangles found on the tail of an orca:

Pretty ridiculous, right?

But then some days you really do find some math out in the real world, and you can’t help but snap a picture:

I mean, holy cow! So many boxes – and one would presume – so many pizzas! I couldn’t help but take a picture and share on Twitter. The photo grabbed the attention of a few folks:

What makes this image so much more compelling than the whale tail? Both are photographs and therefore “real world.” Both have connections to math concepts. And yet one is ridiculous (not in a good way) while the other prompts thoughtful notice and wondering.

To me the difference has to do with two things – novelty and narrative. While there is a tourism industry around whale watching in person, there is nothing particularly novel about seeing a photo of a whale’s tail sticking out of the water. In addition, the textbook photo doesn’t even hint at a story. It’s a tail. It’s sticking out of the water. It’s likely going to go back in the water. Even worse, that flimsy narrative has nothing at all to do with congruent triangles.

The pizza picture, on the other hand, is extremely novel, assuming you don’t work at a pizza parlor. So much so that I felt compelled to not only stop and take a picture but also post it on Twitter for others to see. The picture taunts you with a narrative. What’s going on here? Why are there so many pizza boxes stacked on this table?

I couldn’t help but get to the bottom of it.

As I ate lunch, I watched as the guy put together even more pizza boxes. He eventually spread over two tables, and he kept consulting these long receipts.

I couldn’t help myself. I finally went over and asked who the order was for. It turns out a hospital had ordered 78 pizzas. 78!! Not only that, they had an order for 88 pizzas that afternoon followed by another order of 78 pizzas. And(!) they had an order for 88 pizzas the night before.

I asked how long it would take to make all 78 pizzas. I couldn’t believe my ears when she told me an hour to make them all and 40 minutes to bake them. Holy cow! 78 pizzas in less than two hours?! It just boggles the mind.

And why is a hospital ordering so many pizzas? Here’s a wonderful idea shared on Twitter. I hope it’s true.

Novelty and narrative, two factors that make the real world real and interesting to talk about in math class.

If you happen to want to share this with your students to see what they notice and wonder, here’s the final photo I took of all the boxes stacked up:

And here’s a photo with some additional information about the sizes of pizza and the number of slices. By the way, all of the pizzas in this order were large.