This paper draws upon the sociology of numbers, particularly work by Theodore Porter, to reveal the multifarious ways in which numbers actively constitute practices in schools. Drawing upon a case study of one low-performing school in a low-performing region in the state of Queensland, Australia, and theorising into the sociology of numbers, the research explores the complex ways in which numbers came to constitute and dominate the practices in this school site under a broader national, state and regional policy context demanding rapid improvements in various forms of standardised tests and associated practices. Specifically, the research reveals a strong and simultaneous focus by teachers upon a variety of numeric data collected at national, regional and local levels, and intricate relations between these data; multiple visualisation, triangulation and comparison approaches towards such data in virtual and physical formats; and the enumerative nominalisation of both students and their reading attainment in relation to specific, concretised levels of achievement and various types of scale scores. The research cautions against the sheer volume of such enumerative practices, which, while productive of teachers' understandings of student capacity against standardised measures of achievement, may also lead to a more reductive view of education, dominated by concerns about achievement in standardised tests (and associated practices) alone.