Hi T.A. ... There's no one single numerological system "hard-wired" into the Marseille deck's pip cards. You can use whatever system you feel like. Don't let anyone or any book tell you otherwise. And don't worry about experimenting. It's encouraged.
Use Pythagorean based numerology, RWS/GD-based numerology, "modern numerology", Major Arcana I to X similes, astrological numerology, cabalistic numerology, folk numerology, Biblical numerology, etc.
(Hey! by the way, that's quite a tongue-twister. Try to say "Marseille deck's pip cards", 10 times, real fast.
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The following thread contains, among other things, a discussion of many different and possible numerological approaches to the Marseille pip cards. It contains quite a few posts, by Lee, by me and by various others from the board.
http://www.tarotforum.net/showthread.php?s=&threadid=1614
Personally, at present, I use Major Arcana I to X similes and Pythagorean numerology. I'm also experimenting with modern numerology as well, which in many ways is quite strongly influenced by Pythagorean numerology anyway. You will also find that Pythagorean numerology and Major Arcana I to X similes yield quite similar number meanings. This may be more than coincidence.