# Additive and Multiplicative Situations: Units Coordination

The concept of fractions has been a challenge for children for many years. Researchers at the AIMS Center for Math and Science Education turned to the research of Dr. Leslie Steffe to find out why. The Units Coordination team learned that the difficulties with fractions are related to children’s understanding of whole number and how students can think about whole numbers in more than one way at a time. It became apparent through the work done by Les Steffe that the process of coming to understand whole number is far more sophisticated than adults may realize.

The goal of this team is to learn how children’s additive schemes lead to multiplicative schemes once a child is numerical, and how those schemes relate and contribute to the development of children’s fractional knowledge. A key element in this development is the construction of a composite unit that can be used flexibly by children in addition, multiplication, and in recognizing fractions as numbers. This work adds to our understanding of the continuum that Steffe has identified.

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