Roullete is all about probability so it is more as a luck-based game, I also have known it for a long time but I only played it a few times.  It is like a  toss coin but with an extra feature which is green (like a coin landing on its edge), that can give us a higher multiplier.   The lesser the probability to appear the bigger its multiplier, so I always bet on the green, so when the spin hit it, I got a bigger winning.