This chapter offers an analysis of the segmentation of texts into lists of mathematical problems written on clay tablets during the Old Babylonian period (early second millennium BCE). The study focuses on mathematical series texts, that is, long lists of statements written on several numbered tablets. Two aspects are considered: material segmentation (sections, columns, tablets...) and textual segmentation (statements, groups of statements), as well as the relationship between these two aspects. It is shown that the analysis of parts of text may be a powerful tool for the reconstruction of the entire series and for detecting the operations on texts which produced the series.