Divisibility refers to the ability of one number to be divided by another without leaving a remainder. For example, the number 10 is divisible by 2 because 10 divided by 2 equals 5, which is a whole number. In contrast, 10 is not divisible by 3 since dividing 10 by 3 results in a remainder. To determine if a number is divisible by another, certain rules can be applied. For instance, a number is divisible by 5 if it ends in 0 or 5. Similarly, a number is divisible by 2 if it is even, meaning it ends in 0, 2, 4, 6, or 8.