How to tell if a number is divisible by another number?

We have some rules about that:

1. n is divisible by 2, so it has to end by an even number such as 0, 2, 4, 6, 8.

2. n is divisible by 3, so the sum of its digits is a number divisible by 3

3. n is divisible by 5, so it has to end by 0 or 5.

4. n is divisible by 4, so its two last digits forming a number divisible by 4 like 212, 3 04

5. n is divisible by 9, so the sum of its digits is a number divisible by 9

6. n is divisible by 10, so it has to end by 0.

and there are some other rules like if n is divisible by 2 and 3, so it is divisible by 6