The introduction of the National Numeracy Strategy (NNS) in England in September 1999 represented a very significant attempt to change the way mathematics was taught in primary schools. In Wales, where the NNS does not apply, an alternative strategy required Local Education Authorities (LEAs), in consultation with their schools, to develop locally based numeracy initiatives. This article presents and discusses results from a comparative study of the way in which headteachers viewed these contrasting attempts to raise standards of numeracy and their perception of the way in which the initiatives impacted upon pupils, teachers and teaching approaches. Whilst the data presented within the article may be of particular interest to policy makers and practitioners in England and Wales there would also appear to be some messages for those who may be concerned with similar large-scale reform efforts, elsewhere.