the whole numbers are also known as the natural numbers
Natural number Some definitions, including the standard ISO 80000-2,[1] begin the natural numbers with 0, corresponding to the non-negative integers 0, 1, 2, 3, …, whereas others start with 1, corresponding to the positive integers 1, 2, 3, ….[2][3][4][5] Texts that exclude zero from the natural numbers sometimes refer to the natural numbers together with zero as the whole numbers, but in other writings, that term is used instead for the integers (including negative integers).[6]
Reality In the philosophy of mathematics, the best known form of realism about numbers is Platonic realism, which grants them abstract, immaterial existence. Other forms of realism identify mathematics with the concrete physical universe.