We assess the relationship between numeracy skills and numeracy practices among adults in everyday life and at work from the Survey of Adult Skills, a product of the Programme for the International Assessment of Adult Competencies (PIAAC), an international survey of about 250 000 adults aged 16-65 years old conducted by the OECD in 33 countries/economies. The level of proficiency and the intensity of engagement in numeracy practices are two embedded aspects of numeracy. Proficient adults use numeracy frequently and adults who regularly engage in numeracy practices improve their performance. Individual and contextual factors influence, in different ways across countries, the strength of these links. The intensity of the use of numeracy in everyday life decreases as the lapse of time since a person’s studies increases. Moreover, employed people engage in mathematical activities less in the private setting if they do not do so intensively in the workplace.