Wednesday is pizza day at our school. As I prepared to hand pizza out to my student, a little voice whispered: “#mathematizethis!” So of course I took a picture before passing it around. (To clarify, taking pictures of food is not a thing I usually do!)
Just for good measure, I took this picture too, and I was glad for it.
Today, Thursday, I used these pictures for a Number Talk. I put up the pizza picture and said, “What do you see?”
- There are 2 pieces of pizza missing. (This might not seem like a big deal, but it showed me that they could extrapolate the information by comparing the 2 pizzas. This came about as people said, “There is one whole pizza and one part of a pizza.” And “There are 10 pieces in a whole pizza.” And “I can see 5 cheese, and 3 ham, so two must be missing because we need 10 for a whole pizza.”
- At first, they were all about the counting. (We have done only 1 other fraction Number Talk.) One girl said “I saw 1,2,3,4,5 on one half, so that means 5 on the other half, then 5 on the other half, so that’s 15. Then 3 more, so there are 18 pieces of pizza.” UNITIZING!!! AND SUBITIZING!!!
- Soon after that, the fractions started rolling in.
- 3/18 are ham
- 15/18 are cheese
- 2/18 are missing. (We talked about how it was really 2/20 missing.)
- I asked, “What fraction of the pizza would a person have if they only had 1 piece?” I am super excited that 1 person said 1/10 since we’d established that 10/10 is a whole pizza. Nobody argued for 1/18, and nobody looked confused, so I call that a win.
- There is one milk missing. 9 can fit in the box.
- 1/8 of the milk are plain. 7/8 are chocolate. They went to fractions much quicker the second time.
I asked what they would do if a class ordered more than 9 milks. Most agreed you could stack the milk on top, but some thought a second box would be required.
Overall, I am super-nerdy excited about how this went. It’s a contextualized problem, and one that they will encounter again because pizza comes every week. I am also thinking this could be a Guided Math centre question at the beginning of every month. The number of children who order pizza tends to change a bit every month. AND, we could take pictures of the pizza in other classes.
I am going to teach fractions earlier next year just so I can do this! And then I am going to teach graphing so we can graph our results. I just decided that right now, so if you don’t see this reflected in my long range plans, please hold me to it!