Winning in roulette simply requires a correct prediction of where the ball comes to a stop once the wheel and ball are spun. The wheel consists of 37 partitions in the French and European versions and 39 in the American versions. The partitions are colored in red and green.
This means that apart from betting on specific numbers, players can also predict the colors that will give a return. These bets are placed on a roulette table which has inside and outside bet. Inside bets have a focus on numbers while outside bets are more about 'non-committal' predictions like color or range of numbers.