Question

what're all the numbers divisible by 3 and 9?

Answer 1

3 and 1 are divisible by 3. 3, 1, and 9 are divisible by 9

Answer 2

Now if you're talking about your last question, you're still using this. https://us-static.z-dn.net/files/d93/1c39d6bfe22a33d556dc29ee364f6219.png

So, 27, 72, 45, 81, and 54 are divisible by 3 and 9.