In this chapter, the authors explore what numeracy looks like for young learners in the twenty-first century. They provide examples of how early years learners develop mathematical concepts and processes in a range of contexts, how educators can encourage and support this activity, and approaches to assessment and documenting learning. The Australian Curriculum–Mathematics defines numeracy as ‘the capacity, confidence and disposition to use mathematics to meet the demands of learning, school, home, work, community and civic life’. Reconceptualising essential components of early numeracy takes account of new research that places mathematical content—traditionally preserved for the formal curriculum—in the prior-to-school years. ‘Educators require a rich mathematical vocabulary to accurately describe and explain children’s mathematical ideas and to support numeracy development.’ The authors highlight young children’s capacity for mathematical thinking. They review current perspectives on numeracy within the context of a rapidly changing technological society.