A Case Study of a Highly Skilled Mental Calculator

Abstract

This case study examined the performance of a 13-year-old highly skilled mental calculator on mental multiplication tasks. She solved difficult tasks by using various ingenious calculation methods, including distributing, factoring, and recalling the product directly. She possessed an extensive memory for squares of two- and three-digit numbers. Her WISC-R digit span was much greater than average. She used her exceptional knowledge of calculation methods and verification techniques to ascertain quickly if a number was prime or composite. She claimed to be largely self-taught, and her expertise probably developed through experimentation with numbers and number patterns.