In an attempt to improve education for all students, U.S. educators and employers have independently developed voluntary national standards for academic subjects and for various occupational skill clusters. These standards pose a special challenge to mathematics: to develop a core curriculum suitable for all students that is grounded in authentic, concrete tasks in which important mathematics is embedded in meaningful and realistic problems from life and work. A core curriculum rooted in credible and concrete problems refining only elementary tools will make high school mathematics work for all students. (Contains 21 references.) (Author)