The presence of the mathematics in Plato's dialogues is unquestionable. However, its reach and sense is controversial for some specialists. Some believe that the mathematical themes employed in the dialogues are mathematical fantasies; on the other hand, others defend, based on the Aristotle's testimonies, that Plato would have substituted the intelligible forms by the ideal numbers in his hypothesis. Having not taken part in the quarrel, we propose an investigation on the nature of the numbers based exclusively in Plato's texts, particularly oriented by the a passage in book VII of Republic (525 b11 - c3), in which Socrates says: "Then it would be fitting, Glaucon, to set this study down in law and persuade those who are going to participate in the greatest things in the city to go to calculation and to take it up, not after the fashion of private men, but stay with it until they come to the contemplation of nature of numbers with intellection itself (...)".
Numbers; Plato; Republic; intelligible forms