Question

If HCF of two numbers is $1$, the two numbers are called relatively ________ or ________.

• A. prime
• B. co-prime

Answer 1

Define HCF:

1. The greatest common factor between given two or more numbers is said to be the HCF (Highest Common Factor) of the given numbers.
2. If the HCF of two numbers is $1$, it means that the two numbers have no common factors other than $1$.
3. The numbers having no common factors other than $1$ are called relatively-prime or co-prime numbers.

Hence, if the HCF of two numbers is $1$, the two numbers are called relatively prime or co-prime.