Use of german 5 day pass

You can use the German Rail pass on the S-Bahn in Munich, but not on the U-Bahn, Streetcars or buses of the MVV. For the rest of the transit in Munich you need a Partner Dayticket (Parter Tageskarte). The one for just the inner zone, which has everything you want except Dachau is €9 for 2-5 people (you son is free anyway). If you want to include travel to Dachau, you need a Partner Dayticket for the inner two zones (München XXL for €10,80). Information about the MVV is at www.mvv-muenchen.de.

I think the same is true for the other two cities (Frankfurt and Berlin). The German Rail pass is valid for all DB operated S-Bahns but not for other modes of transportation. And, in Berlin, all of the S-Bahns may not be operated by DB and the pass might not be valid on those that aren't, but I don't have exact information on which ones.

In Frankfurt, Rhein-Main-Verkehrverbund (www.rmv.de), the Tageskarten are priced according to the zones they include. For just downtown Frankfurt, the inner zone (50), a Gruppentageskarte (group day ticket, for up to 5 people) is €8,40. For the two zones including the airport (5090) and downtown, the Gruppentageskarte is €13,70.

BTW, I have spent close to 3 weeks in Munich (in 20 years, 6+ visits), and I have been on other than S-Bahns twice, one time on a bus, the other on a streetcar, both times to Nymphenburg. Other than that, everything has been with the S-Bahn. On the other hand, on only two of those trips have I been on a rail pass.

Thank you very much Lee. I will be coming into berlin from Amsterdam (I am using the 3 country pass since i will be in paris as well). Could i use the 3 country pass to travel from berlin-Dresdner-Frankfurt-Munich.If so,i can then i can buy a 10 day 3 country pass instead of 5 day pass. I would also be able to save on the 5 day german pass.
Then i just buy the day passess for intra city travel.
Pls advice if this is possible or makes much sense.