Our view of learning takes into account how learners, when learning, are engaged in both doing science and mathematics and becoming mathematicians and scientists. Drawing on our work on a number of European projects that developed inquiry approaches across mathematics and science, we propose a new research and development agenda seeking new ways of connecting the subjects. In this article we consider how knowledge might be organised in ways that ensure learners gain insight into how mathematical understanding can prove powerful as they consider how science has applicability in making sense of a range of meaningful situations.