While students progress through their school years, they are expected to develop reading skills in all academic subjects, including mathematics. Mathematics texts, being multisemiotic, require readers to make meaning not only from written language but also from mathematical symbols and visualizations. Integrating content presented through different sign systems is essential for creating coherence. Thus, the organizational structure of these texts becomes critically important when designing texts for learning. The purpose of this thesis is to build knowledge of the organization of mathematical symbols and written language, and to achieve better understanding of how this organization influences the reading of mathematics texts.
First, the structural connections between mathematical symbols and written language in mathematics texts designed for students are characterized. Five distinct categories of such connections—Interwoven, Chunked, Marked, Adjoined, and Referenced—are identified, ranging from connections in which mathematical symbols are integrated into sentences (Interwoven), to those based solely on the proximity between two text sequences (Adjoined). The prevalence of these connection categories in textbooks from different school levels is also investigated. The results indicate a progression in the use of structural connections, with a shift from reliance on proximity in early school years towards a preference for symbols interwoven in sentences between years 2 and 5, suggesting that all students eventually need to navigate texts with interwoven symbols. Additionally, changes can be seen in how symbols are being connected to more detailed meanings. Second, the reading of mathematics texts employing two distinct text designs inspired by the new framework is compared: one design features only sentences with interwoven symbols, whereas the other uses a graphic to highlight key connections between symbols and words. The reading processes and experiences of students are investigated by analyzing gaze measurements and interviews. The results indicate that the two designs have different advantages depending on the situation. While the graphic design can facilitate reading and interpretation by drawing attention to the connections between symbols and words, enabling quicker content matching, the symbols interwoven in sentences might provide better access to details or allow more efficient reading in other contexts. Moreover, individual differences in processing and experiences were noted: while some readers benefitted from the graphic design, others did not. Yet, as reading becomes more complex, the graphic is increasingly appreciated. It is concluded that while readers generally prefer text designs that enhance readability, the optimal design varies based on the reader and the context. The discussion includes what text design benefits whom and under what circumstances.