Natural number, also called non-negative integer, refers to the number used to measure the number of things or express the order of things. That is, the number 0, 1, 2, 3, 4 represents the number. Natural numbers start from 0, one by one, forming an infinite group. Natural numbers are ordered and infinite. Divided into even and odd numbers, composite numbers and prime numbers.

Natural numbers are signs of the same characteristics of all equivalent finite sets. Note: Integers include natural numbers, so natural numbers must be integers and non-negative integers. But the results of subtraction and division are not always natural numbers, so subtraction and division operations are not always true in natural number sets. A number used to measure the number of things or to indicate the order of things.

That is, the numbers represented by the numbers 0, 1, 2, 3, 4, ... the numbers representing the number of objects are called natural numbers, and the natural numbers form an infinite group one after another. Natural number set has addition and multiplication operations. The result of adding or multiplying two natural numbers is still a natural number, and subtraction or division can also be done, but the result of subtraction and division is not necessarily a natural number.

In natural number sets, subtraction and division operations are not always correct. Natural numbers are the most basic of all numbers that people know. In order to make the number system have a strict logical basis, mathematicians in the19th century established two equivalent theories of natural numbers: ordinal number theory and cardinal number theory, which made the concept, operation and related properties of natural numbers strictly discussed.

The origin of 0

0 is an extremely important number, and the discovery of 0 is called one of the great discoveries of mankind. In ancient China, 0 was called Jinyuan number (meaning extremely precious number). This data is said to have been invented by Indians in the 5th century. 1202, a businessman wrote an abacus book. In the east, mathematics is mainly based on calculation.

For some reason, when the symbol "0" was first introduced to the west, it once caused confusion in the west, because at that time, the west thought that all numbers were positive numbers, and the number "0" would make many formulas and logics untenable (such as dividing by 0).