During the 18th century, many newspapers were published in Spain. Many of them covered scientific topics, even if it was not their main goal. In fact, it was possible to find scientific contents in daily newspapers whose main goal was essentially informative. Mathematics was not an exception. In this paper, we focus on the early years of Diario de Barcelona . We have identified the relevant presence of Mathematics in 51 out of the 3013 initial issues of the daily paper. Then, we provide an overview of the mathematical contents presented in this newspaper, that can be classified into two main categories (isolated collaborations and interactions) and, furthermore, we have a closer look at some of these contents. In particular, we describe interactions between readers around arithmetic and algebraic problems proposed by some of them, as well as some isolated collaborations about different topics. In both cases it is possible to detect interesting questions and debates about several aspects of Mathematics.