The aim of this paper is to extend and adapt Yackel and Cobb's (JRME, 1996) identification of sociomathematical norms in mathematical inquiry to problems that are ill-structured. The background theory influenced the design and local theory development of the research. This paper uses excerpts from an upper primary classroom to address the ill-structured mathematical inquiry question, Which bubble gum is the best? Two norms are illustrated: (1) mathematising the ambiguity in an inquiry question, and (2) using the inquiry question to check progress towards a solution. Children demonstrated productive social norms and emergence of the sociomathematical inquiry norm of mathematising, but using the inquiry question was less prevalent. In both cases, children found it challenging to productively coordinate their everyday (relevant) and mathematical knowledge.