A position is represented by a word containing two numbers, such as "No.7 in the ninth row" and "No.5 in the first row", where the two numbers have different meanings, such as "the number of rows" in the front and "the number of numbers" in the back. We call this kind of ordered pair composed of two numbers A and B (A, B), which is often used in plane rectangular coordinate system.
Extended data
A number pair consisting of two sequential real numbers A and B is called an ordered real number pair. The arrangement order of two real numbers will affect the operation result. The most typical ordered real number pair is the coordinate of the plane rectangular coordinate system.
Ordered real number pairs actually represent a point, and they correspond to each other. In a set, an ordered real number pair represents an element.
For example, a set is an ordered real number pair, which represents the number of that point in the coordinate system and is a single-element set. Don't think that you can only write numbers in a set, but you can also write points in a coordinate system, such as (4,5). This is an ordered real number pair.
References:
? Baidu Encyclopedia-Ordered Number Pair Baidu Encyclopedia-Ordered Real Number Pair