Question

HCF of two consecutive odd number is ______.

Answer 1

The set of natural numbers is $\left(N\right)=\{1.2,3,4,5,........\}$.

Among these natural numbers $1,3,5,7,9,.......$ are odd consecutive ones.

It is evident that there is no common factor (except $1$) between two consecutive odd natural number.

So HCF of two consecutive odd natural numbers is $1$.