martins, ana patríciaSousa, Teresa2023-04-192023-04-192022http://hdl.handle.net/10400.19/7763The inclusion–exclusion principle is a simple, intuitive, and extremely versatile result. It is one of the most useful methods for counting and it can be used in different areas of mathematics. In the eighteenth century, the first uses of this result that appear in the literature are related to the study of problems of games of chance. However, the first formulations of this principle appear, independently by several authors, only in the nineteenth century. In this article, we study the formulations obtained by Adrien-Marie Legendre, Daniel Augusto da Silva, James Joseph Sylvester, and Henri Poincaré. We highlight the contribution of the Portuguese mathematician Daniel Augusto da Silva, since his formulation can be applied to different problems of number theory, whenever collections of numbers satisfying certain properties are involved, and this is the reason why his formulation stands out compared with all the others.engjournal article10.1080/26375451.2022.2082158