Getting Classier

I just returned from teaching Excel 1 to adults. Next week I start a 4-week session to mostly the same group -- with a few not carrying over and a few joining anew -- of Excel 2. So, the question is, if I had called the first class Excel 101 would the second class be Excel 102 or Excel 201? What's up with those college-type naming conventions? Hopefully I'm becoming a better teacher each time out and getting classier, to boot.