This research intends to investigate lexical bundles performing a participant-oriented function in mathematics. Drawing on a 5-million-word corpus of graduate-level textbooks, a total of forty-three bundles recurring at least 20 times per million words (pmw) and spreading in 10 % or more of the texts making up the corpus are retrieved and further subjected to structural and functional analyses. On a structural level, results show that the greatest number of participant-oriented bundles are clauses or clause fragments. Functionally, these patterns are used as rhetorical devices for engagement or as means for expressing the author's opinions, judgment and evaluation. Implications for language instruction and materials designing are discussed.