Abstract: Research on how 1st graders develop the concept of unit fractions using problem situations that has them construct their understanding. Dissertation Discovery Company and University of Florida are dedicated to making scholarly works more discoverable and accessible throughout the world. This dissertation, "Acquisition of Fraction Concepts One-half and One-fourth by First-grade Students Using a Constructivist Approach" by Virginia M. Harder, was obtained from University of Florida and is being sold with permission from the author. A digital copy of this work may also be found in the university's institutional repository, IR@UF. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation.