This paper describes the development of a framework of key aspects of early numeracy learning. The framework was developed as part of a project seeking to identify processes for supporting and enhancing numeracy learning in the early years of school. The framework built on work of others, through considering key research in numeracy learning and others' attempts in developing such frameworks. Data collected from one-to-one interviews with over 8000 children led to modifications of the framework. Information is also given on comparisons in students' growth in knowledge, skills and understanding over time in "trial" schools (schools involved in a professional development program at school, region and statewide level) and those in "reference" schools (where teachers have access to interview data, but are not involved in the professional development program).