The students work in groups to share their ideas and reach a reasoned
consensus about their estimates
The class in these video segments is engaged in the estimation and
analysis of data centered first on the number of scoops of cranberries
to fill a jar and then on the number of cranberries to fill the jar. In
this segment, each student makes an estimate of the number of scoops and
then the class organizes their collective estimates in a meaningful
way. Consider what mathematical concepts these students are using. How is
their thinking encouraged, and how else could it be encouraged? Teachers
plan lessons, encourage working groups, and guide class discussions,
all of which influence the extent to which students are likely to make
connections among the many mathematical concepts they are learning.
Throughout this video example, the teacher talks about her decisions as
the students are making estimates and collecting and interpreting data.
What do you notice about how the teacher interacts with the students in
----- Transcript Begins ------Teacher narration: The children naturally know that they have to reach consensus, whenever they are working in a group. They have to work things out and everybody has to feel like they came out with a part of the answer.Girl 2: I'll just say one and a half.Teacher: How do you think you'll figure out how many scoops are in here?Boy 4: Well, there's three already.Teacher: Um huh.Boy 4: And so it might be like six or something like eight or six.Teacher: And how can you figure out if there are eight or six?Boy 4: Because there is already three in there and there is not much room and there is not going to be like fifteen or twenty-two or something.Teacher: Okay, so there is not much room left?Boy 4: No.Teacher: You know there are three in this much.Boy 4: Yah.Boy 5: But what I am asking is if, um, nine was because see three, six, nine.Teacher: Okay, so you actually measured it with your fingers to see how much would be left?Boy 5: Yah.Teacher: That's a good strategy.Boy 5: So I said nine or ten.------ Transcript Ends -----
Keeping each student's attention during whole-group discussions is
often difficult in prekindergarten through grade 2 classrooms unless the
students are involved in the activity. The teacher of the second-grade
class shown in the video is using locally grown cranberries as a
physical material for helping students develop estimation skills. The
activity involves much more than students' looking at a jar of
cranberries and a scoop to make their estimates. The teacher helps the
students examine their estimates using the graph they create. Then (not
shown in these video clips) the teacher and students discuss the range
of responses (from 5 to 22) and the mode, the number named most
frequently. In this way, she takes advantage of a teachable moment to
introduce the concept of mode.
Roche, Robert . "Cranberry Estimation." In Estimating
produced by WGBH Boston. Teaching Math, A Video Library, K–4. Funded and
distributed by the Annenberg/CPB Math and Science Project, P.O. Box
2345, S. Burlington, VT 05407-2345, 1-800-LEARNER.
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