Last Number Master Lock Find Third Number In My Master Lock?

Find third number in my master lock? - last number master lock

I just find the master lock in the past year, and only remember the first two questions, a 2010-model, but I have not the key, because my father for me, someone who has lost the key. . . Who knows how I can find the third number?, Try one after the other? haha

PS I know it is in the wrong section, but could not for the other sections

Aaron