This digest addresses the issue of sex differences in mathematics achievement in K-12 students. The problem is discussed in three sections. The first section examines the progress that has been made in narrowing the gap between girls' and boys' achievement in mathematics and the numbers of women and men who enter mathematics-related careers. Issues addressed include the failure of research to find any inherent differences in girls' and boys' abilities in mathematics, the underrepresentation of women in mathematics-related fields, strategies to motivate girls to take more mathematics courses, and strategies to encourage girls to consider mathematical and scientific careers. The second section offers innovative approaches in mathematics education funded by the Women's Educational Equity Act (WEEA) Project. A list of the products mentioned in the article is provided. The third section discusses a vision of reform from the Urban Mathematics Collaboratives (UMC) that seeks to increase mathematics equity in the classroom. UMC offers a view of equity embodied in six propositions involving: (1) high achievement and high expectations; (2) student access to rich mathematical content; (3) student assessment and equity; (4) teachers' professional development in equity issues; (5) teachers' professional development in mathematics curriculum and instruction; and (6) school restructuring and equity. (MDH)