Applied Mathematics

As for example, take number $11$ .

Factors of $11$ are $1$ and $11$

Therefore, $11$ is a prime number.

Examples of composite number are $8$ , $10$ , $12$ .

Factors of $8$ are $1,2,8$

Example: $(3,5)$ , $(5,7)$

In number theory, two integers $a$ and $b$ are said to be relatively prime, mutually prime, or coprime (also spelled co-prime) if the only positive integer that evenly divides both of them is $1$. That is, the only common positive factor of the two numbers is $1$. This is equivalent to their greatest common divisor being $1$.

Example: $12$ and $17$ are co-primes to each other.