ABSTRACT
In Chapter 2, I discussed the development of number sense, and showed how it is possible to measure it even in infants. Research demonstrated that individual differences in number sense are statistically related to the development of arithmetic and, as I showed in Chapter 3, the critical idea here is that arithmetic is based on a core capacity for understanding the numerosity of a set – that is, the number of objects in a set. This, I proposed, is a necessary tool in the starter kit for the development of arithmetic. In Chapter 4, I showed how a core deficit in this capacity is at the root of dyscalculia. In this chapter, I discuss in more detail with how the core capacity for representing numerosities underlies the development of arithmetic.
