School knowledge versus everyday knowledge – such as workplace knowledge – is a fundamental issue in mathematics education. Mathematics is integrated within workplace activities and often hidden in technology: mathematical elements are subsumed into routines, structured by mediating artefacts (e.g., texts, tools) and integrated in workers’ competences. The so-called “transfer” of mathematics between school and workplace – and vice versa – is not straightforward. However, as a discourse of education, lifelong learning assumes that learning takes place in all spheres of life. This paper discusses terminological and methodological issues related to reversing the one-way assumption from school knowledge to workplace knowledge and to learn from workplace activity what might be appropriate for adult vocational education. It is argued that any working model for researching the dynamics of workers’ mathematics in work and for school has to combine a general approach – starting with demands from the labour market and school mathematics – and a subjective approach starting with the individual’s needs and competences in work. The discussion is based on previous research in the workplace and is a part of an international research project which will analyze and understand adults’ mathematics-containing work competences complementing studies of mathematical qualifications in formal vocational education.