The overall aim of the project was to engage early childhood teachers in investigating and improving their expertise in the teaching and learning of mathematics. The intention of the project was to develop a research environment through which researchers and kindergarten teachers worked collaboratively, using action research methodology, to explore means by which mathematical outcomes for children could be maximised. The research arose from the premise that within the field of mathematics education, while much has been written about mathematical experiences of both learners and teachers in the compulsory (school) sectors of education, very little is documented on mathematical learning and teaching in the early childhood sector from the perspective of the teacher, and particularly within Aotearoa New Zealand. The project engaged the kindergarten teachers through one cycle of action research: from reconnaissance, through intervention, to evaluation. This provided them with opportunities to self-select a relevant issue in mathematics teaching and learning through exploration and reflection on their own mathematics knowledge, their personal dispositions towards mathematics, and their teaching strategies. It was expected that changes in practice would improve mathematical outcomes for children. (author abstract)