15
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...
16
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...
17
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....
18
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...
19
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...
20
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...
21
DescriptionIn the fourth clip Erik repeated the explanation of his model to the classroom teacher. His model consisted of a train of three orange and one dark green rod and lined up four blue rods. He lined up...
22
DescriptionIn the fourth clip from this session, Jessica reported that Jackie and Kelly’s argument was different than their original argument in which they had showed the difference between one half and one...
23
DescriptionIn the second clip from this classroom session, researcher Carolyn Maher posed a challenge. She asked the students to name the red rod if a train of yellow and light green was called two. The...
24
DescriptionIn the second clip from this session, researcher Carolyn Maher asked the students if they felt confident to justify their solution to the problem: Which is larger, one half or one third, and by how...
