A large and representative 10% sample of classrooms consisting of 1,587 students from a mid-western province in Canada was administered a standardized achievement test battery. This battery consisted of four tests, Reading, Mathematics, Written Expression, and Using Sources of Information. Gender and rural-urban differences in achievement and macro- and micro-skills in mathematics were examined. Females, as expected, were superior to males in all except the mathematics test, in which males were better than females. Though Manova results suggested rural-urban differences in achievement, the corresponding Anovas for the four tests confirmed the null hypothesis. An analysis of the mathematics items when grouped into three mental-process or macro-skill categories showed that males were better than females on only the problem solving component. However, males and females from rural classrooms were similar on computation but in the urban classrooms males were better than females. Students from rural classrooms achieved better on concepts than those from urban classrooms. Similarly, an analysis of eight mathematics components, comprising content-specific mental prcesses, produced sex differences on three components and locale differences on two. These findings are interpreted in relation to contemporary theory and research. (Author)