In order to find the greatest common factor (GCF) of the terms, first let's factor the numeric values in their prime factors:
The common factor between these three numbers is the product of the common prime factors, that is, 2 * 2 = 4.
Now, to find the common factor of the variables, we choose for each variable the one with the smaller exponent:
Therefore the common factor is -4(m^5)n.
(we can put the negative signal as well, since all terms are negative).