yes, you are solving a mathematical equation to earn bitcoins, but due to the greediness of companies such as Cointerra, KNC, and Butterfly Labs you will never have a chance to earn a fraction of what they are earning.  Check out this guy:  http://eligius.st/~wizkid057/newstats/userstats.php/1A73ExsM2doRwTLp82rv5U36QHbBFmHD1X .  They are hashing with 900+ TH.  Yep you got it thats TH.  His computer is 1000x faster that your usb miners.   I like you once was interested in mining.  However after months of research and reading dozens of horror stories about ASIC suppliers delivering late, or not at all, i can tell you save your time and money either buy bitcoin or just save it for your kids college fund.