Thought processes involved in counting and comparing small amounts of money were studied among 34 children and adolescents with Down's syndrome or mental retardation of unknown etiology and 15 normally developing first graders. Few intergroup differences were found in children with mental retardation. As complexity of counting tasks increased,…

This study examined the matching and sequencing of quantities, numerals, and arbitrary forms by two individuals with mental retardation. Results showed that sequence training did not readily lead to new matching performances, unlike prior research with college students. Instead, training in matching to sample yielded emergent sequence production…