Incorrect. To find the GCF of two monomials, factor each into primes and variables. Find each prime they have in common and each variable they have in common. For each of those, count how many times they have that factor in common. The GCF should have that many. Here you need to find how many times m appears in both $\displaystyle{30}{{m}}^{{4}}\usepackage{cmbright}\Huge\$ and $\displaystyle{36}{{m}}^{{6}}\usepackage{cmbright}\Huge\$ .