I think the number is the number of the string. You have it set to manual mode. So basically its not automatic so it assumes that the number your doing is the correspondnig string and it seeks that out. I.e. 1 is the high e and 6 is the low e. It will screw up everything if you not corresponding strings. Its on automatic. Basically your tone is corresponding to other string notes as you continue to tune to different pitches. say you start at 6e and start to tighten the string eventually if u dont break it will go to a higher pitch corresponding to other strings...lighter strings ie 5 then 4 then 3 then break!