Fractions, Grade 4, Clip 3 of 4: Multiple models to represent one half

Researcher Amy Martino led a whole class discussion that focused on solutions to the task: I'm going to call the orange and light green together one…Can you find a rod that has the number name one half? Several students provided responses. Andrew used a white rod sandwiched between two dark green rods and explained that the length of one dark green rod and half the white rod was equal in length to one half the length of the orange and light green train (i.e., a composite rod made by laying the rods end-to-end). Brian presented multiple models that could be divided in half to form a new rod that could be called one half if the orange and light green train was called one, after which Meredith provided yet another solution, which was clarified following the researcher's probing by an explanation from Graham. Finally, Erik made a nearly exhaustive attempt to find one half of the length by using thirteen white rods and trying to divide them into equal groups. The researcher concluded the session by discussing how Erik's method could be used if one of the white rods was split into two equal pieces, and each piece assigned to a group.Transcript and student work are also available.Robert B. Davis Institute for Learning. (1993). Fractions, Grade 4, Clip 3 of 4: Multiple models to represent one half. [video]. Retrieved from http://hdl.rutgers.edu/1782.1/rucore00000001201.Video.000054750Available in QuickTime streaming and downloadable Flash digital video files