In mathematics, the capital symbol z is used to represent the set of all integers, including positive integers, 0 and negative integers. According to the new regulations, the set of positive integers and 0 is also called a natural number, which is usually recorded as n.

Commonly used number sets and their symbols;

The set of all positive integers is called positive integer set, which is denoted as N*, Z+ or n+;

The set of all negative integers is called negative integer set, which is denoted as z-;

The set composed of all nonnegative integers is called nonnegative integer set (or natural number set), and is denoted as n;

The set composed of all integers is called integer set, which is denoted as z;

The set of all rational numbers is called rational number set, and it is recorded as q;

The set composed of all real numbers is called real number set, which is denoted as r;

The set composed of all imaginary numbers is called imaginary number set, which is denoted as I;

The set of complex numbers composed of all real numbers and imaginary numbers is called complex number set, and it is recorded as C.