In a 12-year period, in a total of about 2000 new patients referred to our Epilepsy Centre, we observed four patients with seizures exclusively or predominantly triggered by calculation or by card and board games (epilepsia arithmetices, EA). In agreement with observations reported in the literature, all the patients suffered from idiopathic generalized epilepsy (IGE), and probably from juvenile myoclonic epilepsy of Janz. In only one patient was it possible, during arithmetic tasks of increasing difficulty and stress, to evoke electroencephalographic (EEG) paroxysmal discharges, progressively increasing to clinical seizures. In the remaining patients the diagnosis of EA was exclusively clinical, as it was not possible to record EEG interictal or ictal paroxysmal activity specifically triggered by arithmetic tasks. Consequently, it is emphasized that in some cases the diagnosis of EA in a patient with IGE may be based exclusively on clinical criteria. As reported in the literature, it is possible to observe during mathematical calculation or during games both clinical (myoclonic jerks of the right hand) and EEG (localized small spikes) focal signs, which suggest a localized activation of specific areas in a patient with IGE.