TEACHER: Ana, can you tell me how Stephanie knew she needed 25 more
if she started with 75?
ANA: I saw her look at that [pointing to the strategy chart]. It says that
75 25 100.
TEACHER: Ana you did something similar. You chose 92 and then counted
8 more to get to 100.
STEPHANIE: I don’t have 25, but I could do 23. No, wait 24. That gets me
really close.
TEACHER: Could you use 23?
STEPHANIE: I could but then I’m not that close; 24 gets me closer. It’s only
1 away from 25.
TEACHER: Stephanie, does the order of your cards matter when you are
looking at them? What I mean is, do you need to make two-digit numbers
in the order you are looking at in front of you?
STEPHANIE: No, that’s why you said to move them around. At first I didn’t
see the 24 because the 3 was after, but then I looked more.
TEACHER: So how close to 100 did you get?
ANA: 75 and 24 makes 99, so 1 away. I’m a little closer than Stephanie.
TEACHER: Girls, you did a great job. I want you to think about these strate-
gies when you are choosing the four cards. If you select a number, think
about how far away you are from 100 and see if you have something close.
You can also look at the Ways to Make 100 chart to help you get started.Assessing Understanding
I noticed that Stephanie was able to manipulate the numbers into a position other
than what was in front of her. At first I wasn’t sure because she chose 75 and 23, which
came in that order (7, 5, 4, 2, 9, 3). She then selected the 4 to get even closer and
didn’t need to move the cards in front of her. But, I did explicitly point that out to
her that the cardscouldbe moved around, and perhaps that made her more aware.
Stephanie also looked back to the Ways to Make 100 chart that we had created in
the small group before the whole-group lesson. Ana had not been in that group and
I made a mental note that she could probably benefit from the additional practice.
Sharing Strategies
After my intervention with the girls, I felt that they would be able to present
their ideas to the whole class, so I did ask them to share. I was confident that
they would be prepared because of the conversation about strategies we had
while they were working together. As they shared, they focused on referring
BUILDINGUNDERSTANDINGTHROUGHTALK