To Orodruin's question, It's tricky, but my understanding as of now is that, any larger gear driving a smaller one,say 20 teeth gear driving a 10 teeth one would rotate exactly once, so a 40 teeth gear would rotate like 1/2 a rotation? and so on? If I'm right?
Okay, I just tried the experiment with 2 one cent coins and found that thought there were no teeth to simulate it perfectly, the driver coin took almost exactly 2 rotations...
A gear A has 50 teeth and another B has 10 teeth, how many times does the small gear rotate around the big one? I thought 5 but its 6! Note: The gear is curved like 360 degrees.