Investigates the development of understanding of quantity in 36 children with Down's Syndrome. Findings confirmed similarities in sequence of development between Down's Syndrome children and nonretarded children. Down's children who received training recognized conservation of continuous and discontinuous quantity. (RJC)

Examines one preschooler's conversation with author to determine what concepts educators consider "difficult" for this age group. Finds that concepts such as "infinity" and "negative numbers," typically avoided by primary educators, were brought into view in the task-based conversations. Argues that individual…

Through seriation, verbal seriation, and conservation tasks, investigated blind, partially sighted, and sighted children's understanding of quantity. Subjects were 81 children equally dispersed through these 3 groups. Age range was 4 to 17 years. Found similarity in concept acquisition among three groups that extended beyond quantity conservation…