Natural numbers are signs of the same characteristics of all equivalent finite sets. 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.
Therefore, subtraction and division operations are not always valid in natural number sets. 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.
Cardinality theory defines natural numbers as the cardinality of finite sets. This theory puts forward that two finite sets that can establish one-to-one correspondence between elements have the same quantitative characteristics, which are called cardinality.
The benefits of learning mathematics
People who are good at math are relatively smart and savvy, and they can show their advantages in dealing with people. The faster you think, the more ways and ideas you have. Cambridge, majoring in financial mathematics at Carnegie Mellon University in the United States, said that studying mathematics has brought her mental exercise and made me pay more attention to the rigor of thinking in my life.
For example, before solving a problem, I like to divide it into several sections, and each section is divided into several steps, so that I can dig slowly like a branch instead of thinking in confusion in front of a pile of data. Mathematics is the foundation of other disciplines, and it is easier for people who learn mathematics well to get into other disciplines. Learning software, computer, finance and other engineering majors is even more handy.
Can manage money better than others. The application of mathematics in life is everywhere. Nowadays, the society is already an information society, and mathematical knowledge is used in financial management and computers. Warren Buffett is very powerful, but Buffett's power is also based on mathematics. Buffett's decision-making process is actually the method of using subjective probability.