Numeracy is a cross-curricular priority, an intersystemic priority and, of late, a federal government priority. Yet as a priority "numeracy" is inadequately defined and the term is used to describe a wide-range of notions. Many educators are unsure of what constitutes numeracy, unaware of how it differs from mathematics, and uncertain as to how its demands may be met in their planning and teaching. Secondary schools have few models upon which to develop a whole-school numeracy plan. This study describes the journey of a secondary school staff as they developed a shared understanding of numeracy, identified the numeracy demands throughout the curriculum and planned for a whole-school approach to address these demands.