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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....
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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...
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DescriptionIn the third of five clips from this classroom session, David, Erik, and Meredith are building a large model on the floor in an attempt to reconstruct what they had built in a previous session....
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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...
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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...
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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...
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DescriptionIn the fifth of five clips from this classroom session, a visiting researcher asked David, Erik, and Meredith about the large model on the floor, which reflected their attempt to reconstruct the model...
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DescriptionIn the second clip researcher Carolyn Maher stated that the class would be studying pieces of the number line. She referred to the homework from the prior session and stated that the class was...
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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...
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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...
