No numbers is series 7. Series one has 2 sets of 18, Series 2 is set of 25, with some dated 2010, some 2011. Series 3 is 26, series 4 is 27, series 5 is 34, series 6 is 33, series 7 is 19.I am new to these cards and don't have any yet. Lots of information to intake but do have one question for now. Seems some cards have numbers on the back, but other do not. The ones without numbers are they part of a series, if so, which one?