43+ A Whole Number That Is Not A Natural Number Images. If 0 is included in natural numbers, then it is known as whole zero (0) is not a natural number but a whole number. Natural numbers can mean either counting numbers {1, 2, 3,.}, or whole numbers {0, 1, 2, 3,.}, depending on the subject.
So zero is a natural number as a consequence of how we define the natural numbers.
Complex numbers are opposites of real the only number which is a whole number and not a natural number is none other than 0. So there you go, not everyone agrees on a simple thing! Pros of considering $0$ not to be a natural number: Natural numbers start from 1, 2, 3, 4, 5,….and so on.