Roulette is a game specifically designed to benefit the house, and it is naive to think that casinos would have any games that would make them loose money. Roulette games can be won, but the chances of loosing are greater than the chances of winning – in modern times that is. In the past some people got rich because they knew where roulette games were offered where the system, or rather the wheel, was rigged. The players would then bet against the high stakes players and thus make their fortunes that way.
Since then the casinos are making certain that their roulette wheels are properly balanced and spin evenly so that the outcome of the game is not biased either way. Two roulette systems exist, but the American roulette wheel with a single layout has become the most used around the world. Even in that setup there two types of wheels: the single 0 and the double 0 or 00. The odds are slightly different for each, but the rules of play are the same.
Even today there exist several systems where people claim that they can win at roulette. The simplest of this is using past outcomes to predict future outcomes. In a system that plays fair, the odds of the outcome of the next round is the same as it had been for the previous round, and cannot be predicted in that way.
Several strategies are available, and many of them guarantee that you will win. Systems like even-money bets, progressive betting, pyramid betting and so on. They all rely on the fallacy that a player is more likely to win after a loss and vice versa. Do not be fooled by this as the likelihood of loosing will remain higher than winning no matter which system you use.
Odds are better if you play more combinations, like red numbers and / or even numbers at the same time, but the outcome is no guarantee. And that is where most people make the mistake. There are mathematical models to describe roulette, but in the end it is a game of chance and the risks associated with that has be taken into account.