It is called as Natural number to that number that allows counting the elements of a set. The 1, 2, 3, 4, 5, 6, 7, 8 ... are natural numbers.
It should be noted that these were the first set of numbers that humans used to count objects.
This type of number is unlimited, that is, whenever the number is added one to one, it will give way to a different number.
The two great uses of natural numbers are, on the one hand, to indicate the size of a finite set, and on the other hand, to account for the position that a given element has within the framework of an ordered sequence.
Also, natural numbers, at the behest of a group, allow us to identify or differentiate those elements present in it. For example, in a social work, each affiliate will have a member number that will distinguish him from the rest and that will allow him not to be confused with another and have direct access to all the details inherent to his attention.
There are those who consider 0 as a natural number but there are also those who do not and separate it from this group, the theory of sets supports it while the theory of numbers excludes it.
Natural numbers can be represented in a straight line and ordered from least to greatest, for example, if zero is taken into account, they will begin to be noted after this and to the right of 0 or 1.
But the natural numbers belong to a set that brings them together, that of the positive integers and this is because they are neither decimal nor fractional.
Now, as regards the basic arithmetic operations, addition, subtraction, division and multiplication It is important to point out that the numbers we are dealing with are a closed set for addition and multiplication operations, since when operating with them, the result will always be another natural number. For example: 3 x 4 = 12/20 + 13 = 33.
Meanwhile, this same situation does not apply to the other two operations of division and subtraction, since the result will not be a natural number, for example: 7 - 20 = -13 / 4/7 = 0.57.