In two experiments we evaluated the coactivation of arithmetic facts and the possible inhibitory mechanism used to select the correct one. To this end, we introduced an adapted version of the negative priming paradigm in which participants received additions and they decided whether they were correct or not. When the addition was incorrect but the result was that of multiplying the operands (e.g., 2 + 4 = 8), participants took more time to respond relative to control additions with unrelated results. This finding corroborated that participants coactivated arithmetic facts of multiplications even when they were irrelevant to perform the task. Moreover, the participants were slower to respond to an addition whose result was that of multiplying the operands of the previous trial (e.g., 2 + 6 = 8). These results support the existence of an inhibitory mechanism involved in the selection of arithmetic facts.