Varieties of computational estimation were explored in relation to other mathematical skills and sex differences. The subjects were eighth graders (144 girls and 165 boys) from seven schools. Open-ended estimation was the most difficult, followed by estimation relative to a reference number and estimation within an order of magnitude. Verbal tasks were not more difficult than numerical tasks, but decimals were more difficult than whole numbers, and quotients were more difficult than products, which in turn were more difficult than sums and differences. Boys scored higher than girls on the total estimation test and on the order of magnitude scale. Stepwise regression analyses indicated that estimation performance was best predicted by skill in operating with tens.
Rheta N. Rubenstein, Mathematics Department Head, Renaissance High School, 6565 W. Outer Drive, Detroit, Ml 48235