The numbers "21-30" represent a range of integers that follow the number 20 and precede the number 31. This range includes the numbers 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30. Each of these numbers has its own unique properties and uses in mathematics, such as being used in counting, ordering, and various calculations. In many cultures, reaching the age of 21 is significant, often associated with legal adulthood and the ability to partake in activities like drinking alcohol in the United States. The number 30 is also notable, often marking the end of a decade in age, such as turning 30 years old, which can symbolize a transition into a new life stage.