It's six! And I didn't even need to count them!

The number of New Zealand primary school children involved in mathematics interventions funded by the Ministry of Education is increasing, with many intervention teachers claiming lack of number sense as the cause. This study’s aim is to explore what mathematical experiences promote number sense-making for children in their first year of school. In the first cycle of action research, this case study explores how young children respond to mathematical experiences using a variety of materials commonly found in New Zealand classrooms. Analysis of how young children responded informs a second action research cycle during which a new curriculum resource is designed, with the potential of exploring groupings to 5, with 5, and to 10. Mathematical experiences associated with the new curriculum resource are implemented and data is presented about how young children were using conceptual subitising and part-whole thinking when engaging with activities using the new resource. This informs a further action research cycle where data is presented about what young children ‘visualised’ when shown representations of 5 and of 10. Five new entrant children from a mid-decile primary school participated in 17 activity-based sessions and one individual interview. Data collection tools used to gather information about how the children interacted and responded as they participated in the activities included observations, field notes, teacher planning, children’s work samples, photographs of representations children made, and individual interviews. This study presents a dynamic new curriculum resource which, when used within a ‘learning system’, enabled children to be agentic, and to manipulate, create, and re-create representations of numbers in sense-making ways. The most important finding, illustrated throughout this study, is the powerful influence of subitising for promoting part-whole thinking in young children. Using the new curriculum resource designed during this study, 5 year old children were subitising, noticing patterns, and combining and partitioning numbers to 5 and to 10. Findings from this research suggest that children can learn about counting processes, part-whole relationships and number patterns simultaneously, in their first year of school