In the CANDY lab, we investigate the development of numerical abilities from childhood to adulthood until old age. Preschool and school-aged children with or without developmental or learning disabilities are of special interest to us. The main topics we study are related with mental arithmetic and finger counting and one of our main goals is to understand the nature and the structure of the mental representations underpinning numerical activities. An application of our studies is, for example, to understand the difficulties that children and even adults encountered with mathematics and to help them overcoming those difficulties. In order to fullfill our objectives, we mainly study indidividuals’ behaviours towards numbers but we also observe their neuronal correlate using brain activity recording technics.