Students are asked to take the words of the story and make a math picture. No question is asked yet. The story is: “Maria saved $24. She saved 3 times as much as Wayne.”
BECCA SHERMAN: Let’s try, we’re gonna, we’re gonna hang on right here and I’m gonna ask you guys to try on another student’s strategy. And that’s-- I want you to think about this student, Charlie, and how Charlie did it from another class. Whose papers did I take? Not at this school, you guys know I’m not just at this school. Who else? Thank you.
STUDENT: Pretend Charlie?
BECCA SHERMAN: A pretend Charlie, okay. Okay, you caught me! It’s a pretend Charlie. But, this is another way to think about this. So, here’s how Charlie thought about it. Here’s Maria’s money. How much money did Maria save?
STUDENT: 24 dollars.
BECCA SHERMAN: $24. So we can see that in Charlie’s picture? What about Wayne’s money? How come you think there’s a question mark here? Why would Charlie put a question mark by Wayne’s money? What do you think?
STUDENT: Because he wanted to know how many money does Wayne has.
BECCA SHERMAN: Okay. And what do you think these green boxes, what does that have to do with our problem? What do you think?
STUDENT: Um, maybe it’s like, um, the 24 is there, and pick a number.
BECCA SHERMAN: we have to pick a number. And they’re all the same, so we’re gonna have to pick the same number. Equal groups have to go in these boxes. There’s one more question mark. What do you think that question mark is about? What do you think?
STUDENT: Total of all their money.
BECCA SHERMAN: Okay. Did you guys hear that? His idea?
BECCA SHERMAN: Okay. So, flip your paper over, try and draw it Charlie’s way, and fill in the missing numbers. Okay? Try Charlie’s way and fill in the missing numbers. Why don’t you guys go back to your desks, so you have something hard to write on? Just come on up at your desks so you have something nice and neat to write on. They could, but they’re gonna go back to their desks. Can you try Charlie’s way, so copy down what’s up there, and then what numbers do you think are missing? In that total box, if you can. Yeah.
BECCA SHERMAN: Maria has what?
STUDENT: Can I write it down there?
BECCA SHERMAN: You want to get closer? Is that what you’re saying? Oh, yeah.
STUDENT: I want to write the 24. Down.
BECCA SHERMAN: You can write it below. Yeah. Oh, no, you know what, I’ll do one more.
We designed this part of the lesson in a “re-engagement” teaching structure, which refers to introducing another strategy for all students to think about and try out. To achieve this, I call the bar model picture “Charlie’s way”.