Write the sum of 18+27 as the product of their gcf and another sum

Factors of 18: 1; 2; 3; 6; 9; 18

Factors of 27: 1; 3; 9; 27

GCF (18; 27) = 9

18 + 27 = 9 * 2 + 9 * 3 = 9 * (2 + 3)

18+27=45

factors of 18 are 1,2,3,6,9

factors of 27 are 1,3,9

gcf=9

9x5=45

I'm not positive if this is the answer. I'm a little confused about "another sum". I'm not sure if its asking for another factor of the two numbers or just another number. But I think what I did is right. I'm sorry if I'm wrong.