,

Find the common factors for the numerical part:

The factors for are all numbers between and , which divide evenly.

Check numbers between and

Find the factor pairs of where .

List the factors for .

The factors for are all numbers between and , which divide evenly.

Check numbers between and

Find the factor pairs of where .

List the factors for .

List all the factors for to find the common factors.

:

:

The common factors for are .

The GCF (HCF) of the numerical factors is .

Find the HCF 21 , 56