This article reports on a Swedish research project on the reintroduction of national tests in mathematics for nine- to ten-year-old pupils. Data were collected over a period of three years (2010-2012) by video recording test situations in different classrooms and by conducting video-stimulated recall interviews with children. The aim is to explore and analyse the testing situation and how it creates different positions for children. We conclude that discourses of testing, caring and competition, sometimes strengthening and sometimes shadowing each other and thereby, produce knowledge in children about success and failure in mathematics, positioning children as ‘winners’ or ‘losers’. The tests are interpreted as a technology – a form of disciplinary power that functions at the level of the body (Foucault, 1980).