I'm doing some exercises out of a beginner guitar book, and in the guitar tabulature for the G major chord, for the low E string, it looks like one number is superimposed on top of another--a 3 and maybe a 7?!? I might have thought it was a typo but it's in several spots. The book discusses alternate fingering but that doesn't seem to be related. I've looked through the book and done a web search but haven't been able to find anything similar, so thought I'd see if I could get some answers here. Thanks!