to be a gcf of a number, they have to all divide by it evenly so if 2 is a gcf of 12 and 6 then 6/2=3 =whole and 12/2=6=whole so
therefor we can just introduct other factors which are not equal just multiply 16 by 3 prime numbers or different numbers 16 times 2 =32 16 times 3=48 16 times 5=80