This paper examines perspectives regarding the mathematical skills expected of adults and school graduates, comparing ideas developed as part of two major multinational comparative assessments of skills: the Programme for International Student Assessment and the Programme for International Assessment of Adult Competencies (also known as the OECD Survey of Adult Skills). The paper reflects on the conceptual and assessment frameworks developed for these two programmes, aiming to shed light on the commonalities and differences between the constructs of numeracy and mathematical literacy and to inform current debate about directions for developing mathematical skills in the 21st Century.