This paper analyzes the importance of numerical abilities, conscientiousness, and financial literacy for individuals' financial decision making and participation in formal financial markets. Our analysis is based on the Financial Capabilities Survey, which was applied in four countries of the Andean Region: Bolivia, Colombia, Ecuador, and Peru. The empirical analysis underlines the centrality of numerical abilities, different subfacets of conscientiousness (propensity to plan, perseverance, and scrupulosity), and financial literacy in developing a propensity to save and borrow, and in participating in the formal financial sector.