Question

Find out the highest common factor of $21$ and $28$.

Answer 1

Solve for the HCF of the given two numbers

The factors of $21=1,3,7,21$

The factors of $28$ $=1,2,4,7,14,28$

The common factors of $21$ and $28$ is $1,7$

Hence, the highest common factor of $21$and $28$ is $7$