The nature of numeracy implies that both mathematics and social context are involved. In the Australian curriculum, numeracy is included as one of seven general capabilities that it is the responsibility of every teacher to develop in their students. Many teachers, however, dislike or actively avoid mathematics. This situation tends to lead to opportunities for numeracy development in school students to be overlooked or ignored. A key issue is then to help teachers to recognise the appropriate mathematical ideas in subjects other than mathematics, and then to suggest ways in which these ideas can be acknowledged and developed in context. Three different approaches to working with both pre- and in-service high school teachers are described and the outcomes discussed in the context of building professional capital. Findings suggest that teachers do not recognise the complexity of numeracy, and benefit from supportive professional learning developing professional capital with respect to numeracy.