In this work, we consider equitable proper labellings of graphs, which were recently introduced by Baudon, Pilśniak, Przybyło, Senhaji, Sopena, and Woźniak. Given a graph G, the goal is to assign labels edges so that (1) no two adjacent vertices are incident same sum labels, (2) every assigned about number times. Particularly, aim at designing such k-labellings G with k being as small possible....