prime and composite!!!

P and C is a little tricky to me but I'll show you all I know...
here's how you tell it's prime: it can only divide by 1 and it's self.
here's how you tell it's composite: it can divide by 2 or more pairs like say it's 6, it can divide by 1,2,3, and 6. So the pairs are: 1 and 6, and 2 and 3.


Here's some questions...

Is 11 prime or composite?
it's prime.
Is 81 prime or composite?
composite, by: 1,9, and 81.
 Oh ya I forgot that if it's like 9 it's still composite because it has 3x3 in it but it would just look like this 1,3, and 9.
so that's it, see ya later!!!