In America, education has long been viewed as the main instrument for achieving equality of opportunity. Despite many reform efforts over the past several decades, the US educational system has patently failed to ensure equal access for all to the essential knowledge, skills, problem-solving abilities, and reasoning abilities that are necessary to succeed. Instead, American schools exhibit pervasive inequality. Pervasive inequality is a bold claim, but that's the inescapable conclusion of more than 20 years of examining mathematics and science standards, student achievement, textbooks, standardized tests, and classroom content coverage. In mathematics, for instance, students are exposed to widely varying content not only across states and school districts but within schools. Such inequities in content coverage deny students equal learning opportunities. By the time they enter middle and high school, those students fortunate enough to have been challenged with rigorous, focused, and coherent content in the early grades are placed into courses that continue to challenge them, while their peers who were not exposed to such content are tracked into lower-level courses. And so the differences in learning opportunities that contribute to the achievement gap only continue to grow. These problems aren't found only in lowest-performing schools; the "typical" US student does not receive the content coverage needed to compete with students in other nations. In this article, the authors move from demonstrating the existence of pervasive inequality to considering what to do about it. In particular, they examine the prospects for the Common Core State Standards for Mathematics (CCSS-M) to reduce inequalities in opportunity to learn. They discuss why the CCSS-M "could" provide greater equality of educational opportunity, and they offer some ideas about how to overcome the principal obstacles to successful implementation. (Contains 11 endnotes.)