Number twinning means that the sum of two or more numbers is equal to a given number. For example, if you are looking for the even number 1 1, you can find that the two numbers of the even number 1 1 are 5 and 6, because 5+6 = 1 1.

Mathematics has a lot to do with number pairs, because mathematics is a subject used to describe concepts such as quantity, structure, change and space. Number pairing is a relatively simple mathematical concept, which can help people find two or more numbers quickly through addition operation and make their sum equal to a given number. Therefore, mathematics and counting twins are closely related subjects.