Countries across the world have seen a growing gap in mathematics performance between low-SES children and those from wealthier backgrounds. The issue of inequality not only relates to student performance, but also to schooling--as defined by the mathematics curriculum and its distribution of the related opportunities to learn. Whether relationships between student background, schooling (curriculum coverage), and performance varies between countries with different levels of development has become a question of particular interest to countries and their curriculum-related policies. Those same countries want to achieve both international recognition for excellence as well as equality. Relatedly, the policy question that has arisen is whether both excellence and equality can be achieved simultaneously. The answers to both questions are complex as the relationships between the three key concepts vary among the 63 PISA countries by substantial amounts. Additionally, the averages between the three types of countries vary as well. This all leads to the conclusion that the probability of achieving both excellence and equality varies by the wealth of the country.