What lies between 15 and 16 on a number line?

Between 15 and 16 on a number line lies all the decimal numbers ranging from 15.0 to 15.9, including values like 15.1, 15.5, and 15.9. Additionally, there are infinitely many other numbers, such as 15.01 or 15.999, which are also located between these two whole numbers. Essentially, the interval between 15 and 16 contains an infinite number of real numbers.