44s4t2, 84s2t Break each down to the product of primes and single letter factors: 44s4t2 = 2·2·11·s·s·s·s·t·t 84s2t = 2·2·3·7·s·s·t Pick all but only the factors that they have in common which are two "2"'s, two "s"'s and 1 "t". GCF = 2·2·s·s·t = 4s2t Edwin