GimmeFive supports students in developing efficient and effective mental calculation strategies for performing additions and subtractions of two-, three- and four-digits numbers. This app can be used from each student and in particular from students who struggle in mathematics and from students with learning disorders, like dyscalculia. GimmeFive was designed and implemented by DiDiMa srl in collaboration with the Institute for Educational Technology – National Research Council in Genoa, inside the Project Fondo Sociale Europeo Regione Liguria 2007-2013 Asse IV.