Competencies in numeracy skills correlate with success for students with special educational needs (SEN) in mathematics in later years; however, many students with SEN lack a sound foundation in numeracy skills. For this population, the gaps in skills may widen as students progress through their academic years, making it more difficult for them to access the general curriculum. Consequently, students may leave school without the skills needed for their daily lives in the new millennium. The students’ attainment in number sense impacts on their success in gaining deeper grade-aligned content knowledge of mathematics. In this article, we consider  how these students acquire and generalise numeracy skills. One important factor in the failure to learn arithmetic in the normal way is a core deficit in the sense of number. This has been associated with low numeracy in general, and with dyscalculia more specifically. This article also provides a conceptual framework of policy from Turkish experience including teaching numeracy skills to students with SEN; those educated in both special and general education settings.