1 and natural number set are nonnegative integer sets. The set is called natural number set, and it is recorded as n;
2. The set of all positive integers is called positive integer set, and it is denoted as N*, Z+ or n+;
3. The set composed of all integers is called integer set, and is denoted as z;
4. The set of all rational numbers is called the set of rational numbers, which is denoted as Q;
5. The set of all real numbers is called the set of real numbers, which is denoted as R. ..
6. The set of complex numbers composed of all real numbers and imaginary numbers is called complex number set, and it is recorded as c.
A set refers to a set of concrete or abstract objects with certain properties, called elements of a set, and a number set is a number set.
The range of set is greater than that of number set, and number set is just one kind of set. What belongs to a number set must belong to a set, and what belongs to a set is not necessarily a number set.
Extended data:
Introduction to natural numbers:
Natural number set is a set of all non-negative integers, usually represented by n, and there are infinitely many natural numbers.
Second, the positive integer introduction:
Like an integer, a positive integer is a countable infinite set. In number theory, positive integers can also be called natural numbers, that is, 1, 2, 3 ...;
But in set theory and computer science, natural numbers usually refer to non-negative integers, that is, the set of positive integers and 0. It can also be said that all natural numbers other than 0 are positive integers. Positive integers can be divided into prime numbers, 1 and composite numbers. Positive integers may or may not have a plus sign (+).
Three. Introduction to integers:
Integer is a number like -3, -2,-1, 0, 1, 2,3, 10.
All integers form an integer set, which is a number ring. In the integer system, zero and positive integers are collectively called natural numbers. -1, -2, -3, …, -n, …(n is a non-zero natural number) are negative integers. Positive integers, zero integers and negative integers form an integer system. Integers exclude decimals and fractions.
Four. Introduction to rational numbers:
Rational number is one of the important contents in the field of number theory and algebra, and it is widely used in real life. It is the basis for continuing to learn real numbers, algebra, equations, inequalities, rectangular coordinate systems, functions, statistics and other mathematical contents and related disciplines.
The set of rational numbers can be represented by the capital black orthographic symbol Q, but Q does not represent rational numbers. The set of rational numbers and rational numbers are two different concepts. The set of rational numbers is the set of all rational numbers, and rational numbers are all elements in the set of rational numbers.
Brief introduction of verb (verb's abbreviation) real number;
Real numbers can be divided into rational and irrational numbers, or algebraic and transcendental numbers. Real number sets generally use black letters? r？ Express delivery. R stands for n-dimensional real number space. Real numbers are uncountable. Real number is the core research object of real number theory.
References:
Baidu encyclopedia natural number
Baidu encyclopedia positive integer
Baidu encyclopedia integer
Baidu encyclopedia rational number
Baidu encyclopedia real number