ABSTRACT
It is well known that individual differences in arithmetical performance are very marked in both children and adults. For example, Cockcroft (1982) reported that an average British class of 11-year-olds is likely to contain the equivalent of a 7-year range in arithmetical ability. Despite many changes in UK education since then, including the introduction of a standard National Curriculum and a National Numeracy Strategy, almost identical results were obtained by Brown, Askew, Rhodes, Denvir, Wiliam, Ranson, and Millett (2002). They found that the gap between the 5th and 95th percentiles on standardized mathematics tests by children in Year 6 (10-to 11-year-olds) corresponded to a gap of about 7 years in ‘mathematics ages’. Individual differences in arithmetic among children of the same age are also very great in most other countries, although some studies suggest that they are less pronounced in Pacific Rim countries (TIMSS, 1996).
