The concept of number set T is very flexible. Common number sets include natural number set, integer set, rational number set, irrational number set, real number set and complex number set. Natural number set is the most basic set of numbers, including positive integers and zeros; Integer set includes natural number, negative integer and zero; The rational number set includes integers and all fractions whose denominator is non-zero integers; Irrational number set refers to all real numbers that cannot be expressed as rational numbers; Real number set includes all rational numbers and irrational numbers; Complex number set consists of real part and imaginary part, which is usually expressed by a+bi (the square of I is equal to-1).
The number set T is widely used in mathematics and is often used to solve various mathematical and practical problems. For example, in operational research, set T is often used to describe the quantity and quality of goods. In probability theory, the number set t is often used to describe the possibility of random events; In numerical calculation, number set T is often used for numerical approximation and error analysis. In calculus, the number set T is often used to describe the domain and value of a function. In a word, number set T is a very important basic concept in mathematics, and it is the basis of research in various disciplines.