To find the GCF of the two terms, continuous division must be done. What can be used to divide both terms such that there is not a remainder? Start small, let's take 2. It could be a GCF. Move up higher, say 3. Yes, it can be a GCF. To see if there might be a greater common factor, divide the constants by 3. 48/3 = 16 81/3 = 27 Upon inspection and contemplation, there is no more common factor between 16 and 27. So, 3 is the GCF.
Moving on, when it comes to variables. The variable with the least exponents is easily the GCF. For the variable m, the GCF is m2 and for n, the GCF is n.
Combining the three, we have the overall GCF = 3m2n
