For what it's worth, Rosen's introductory text on discrete mathematics is pretty good as well. (This sort of math crops up all the time in formal CS, for those of you who might otherwise wonder wtf discrete has to do with anything.) http://www.amazon.com/s/ref=nb_sb_ss_i_0_13?url=search-alias... (The study guide that is available to go with it is worth the money, imho.)

The Graham, Knuth, Patashnik book on concrete mathematics (a bit of a play on words for continuous and discrete) is a quality work as well but written to a considerably higher level that may or may not be pleasant to contend with depending on the reader's background. http://www.amazon.com/Concrete-Mathematics-Foundation-Comput...