Children's estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1--100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three…

Developmentally appropriate, psychometrically sound instruments are needed to assess young children and evaluate learning programs. In the United States, little guidance exists on the development and use of large-scale assessments that cover the broad range of skills that encompass young children's development. In 2005 and 2006, the State of…

This experiment aimed to expand previous findings on the development of mental number representation. We tested the hypothesis that children's familiarity with numbers is directly reflected by the shape of their mental number line. This mental number line was expected to be linear as long as numbers lay within the range of numbers children were…