Divisibility rules are a set of rules or criteria that can be used to determine if one number is divisible by another number without actually performing the division operation. These rules are helpful in quickly identifying factors or multiples of a given number.

Here are some common divisibility rules:

1. Divisibility by 2: A number is divisible by 2 if its last digit is even (0, 2, 4, 6, or 8).

2. Divisibility by 3: A number is divisible by 3 if the sum of its digits is divisible by 3.

3. Divisibility by 4: A number is divisible by 4 if the number formed by its last two digits is divisible by 4.

4. Divisibility by 5: A number is divisible by 5 if its last digit is either 0 or 5.

5. Divisibility by 6: A number is divisible by 6 if it is divisible by both 2 and 3.

6. Divisibility by 9: A number is divisible by 9 if the sum of its digits is divisible by 9.

7. Divisibility by 10: A number is divisible by 10 if its last digit is 0.

These rules can be extended to other numbers as well, such as 7, 8, 11, and so on, but they may be more complex and less commonly used.