This chapter reviews the cognitive and neural mechanisms for numerical and mathematical development. It provides converging evidence that from a rudimentary, non-symbolic "number sense" representation that is assumed to exist even in non-human species, the human mind develops its unique symbolic representational system to accurately represent and manipulate numerical quantities. This process is non-trivial, it is slow, and it requires the push-and-pull of multiple neurocognitive systems. These include: (i) those supporting visual and verbal perception/decoding in the occipital and temporal cortices, (ii) regions of the frontal eye-elds and the posterior parietal cortex involved in active manipulation and updating processes, (iii) memory association processes within the medial temporal lobe, and (iv) executive control processes anchored in the frontal cortices. The present chapter proposes a neurocognitive model whereas the successful acquisition of our modern symbolic code for mathematics is gradually re ned through the dynamic interaction of these neurocognitive systems throughout development. Depending on the speci c cognitive weaknesses of the individual, training, intervention, and educational approaches should hence be designed to comprehensively "stimulate" part or all these neurocognitive systems to achieve the most optimal learning outcomes.