Natural numbers do not include decimals. Natural number refers to the number used to measure the number of things or to indicate the order of things, that is, the number represented by numbers.
Natural number
Natural number (including positive integer), but it does not include decimal. Decimals belong to integer items. Natural numbers form an infinite collective from beginning to end.
The natural number set n refers to the set that meets the following conditions:
① There is one element in n, recorded as
② Each element in n can find an element in n as its successor.
③ Successors.
④ Is the successor of any element.
⑤ Different elements have different successors.
⑥ (Inductive axiom) Any subset m of n, if m, and as long as x is in m, it can be inferred that the successor of x is also in m, then m=n.
Natural sequence is the most widely used in "sequence", because in all sequences, the serial number of each item constitutes a natural sequence. The general term formula of any sequence can be regarded as the fixed quantitative relationship between the number of each item in the sequence and its serial number.