19
DescriptionIn the seventh clip, Erik and Alan worked to extend their model using the orange and red train to show fourths and halves. They concluded that three fourths was larger than two thirds by one twelfth....
20
DescriptionIn the second clip, Kimberly and Audra worked together on the task: Which is larger one half or three fourths. Kimberly built a model using an orange and red train, two dark green rods, and four light...
21
DescriptionIn the fifth clip Michael and Brian extended their model using the orange and red train to show thirds and twelfths in addition to fourths. They showed that the difference between two thirds and three...
22
DescriptionIn the fourth clip, researcher Alice Alston worked with Gregory and Danielle on the task: Which is larger two thirds or one half and by how much? Danielle built two models, one using the dark green...
23
DescriptionIn the third clip, researcher Amy Martino then worked with Mark and Laura. Mark justified his solution using each model he built. The researcher asked Mark if he thought that a different model might...
24
DescriptionIn the first clip a visitor worked with Danielle and Gregory on the second task of comparing two third and one half. Danielle showed her using the twelve-centimeter long model, that three fourths was...
25
DescriptionIn the second of five clips from this classroom session, Alan worked alone at his desk on a new task that the researcher, Amy Martino, had posed. He built models to find the difference between one...
26
DescriptionIn the fourth of five clips from this classroom session, the researcher, Amy Martino, returned to Alan and questioned him about the third model that he had built for finding the difference between one...
27
DescriptionIn the second clip, David and Meredith worked on building models to represent their solution to the problem: Which is larger, two thirds or three quarters, and by how much. David first built two...
28
DescriptionAmy Martino introduced division of fractions by asking students to describe how many white rods equal an orange and red train. She then asked the students to name the white rod if the orange and red...
