This paper shows how Latina, immigrant mothers expanded their mathematical boundaries by participating in a community mathematization project. These mothers were not only participants, but also curriculum designers in collaboration with university researchers. By involving the mothers in the design of the project, researchers improved the likelihood that the project would reflect Latina/o "funds of knowledge" and capitalize on Latina/o epistemology. This contrasts with typical approaches to mathematics teaching and learning that ignore the knowledge of parents or do not define them as collaborators. The data collected by children and parents from community sites were collaboratively analyzed by teams of undergraduate student facilitators, elementary students, parents, and researchers. The final products were digital stories that illustrated the mathematics in the daily operations of a particular community site as well as posed a potential mathematical problem that the worker might encounter. Our findings reveal the mathematics that is evident to the mothers, as well as how social networks function to support Latina parents' development of mathematical knowledge and agency.