Question

what are prime and composite numbers

Answer 1

A prime number has only two factors: 1 and
itself. A composite number has more than two
factors.

Answer 2

any number which has only two factors i.e 1 and itself is called prime number
example :
f(2)={1,2}
f(5)={1,5}
any number other than prime is called composite number
or
any number it has morethan two factors are called composite
f(6)={1,2,3,6}