As highlighted in the literature, one of the main difficulties in mathematics is the management of different semiotic representations. This difficulty occurs in verticals throughout schooling and is often an obstacle to the proper learning process of mathematics. The present study aims to investigate the different facets of these difficulties with regard to mathematical tasks in secondary school. In particular, questions from Italian large-scale mathematics assessments are analyzed and interpreted through the theoretical lens of Duval's (1993) theory. Statistical analyses on a robust national sample allow a framing of the main difficulties and provide valuable information in this field.