After every spin, the probability of hitting any number or bet is the same as if you made the bet on the previous spin. Let's say that number 8 came up. The probability or likelihood that another 8 will land is 37:1 (European) or 38:1 (American). However, if you bet that 8 will come up twice in a row, the odds are 1,369:1 (European) and 1,444:1 (American). This simple example is to reiterate that after each spin, the odds of anything rolling is if no spin had occurred previously. The odds of anything landing after a spin are listed in the table above. So if 20 reds have landed in a row, the odds of another red hitting (21 reds in a row) is 48.65% (European) and 47.37% (American). As the result of any new spin is not affected in any way, shape or form, by the previous spin, the odds are slightly less than 50/50 that another red would hit, which is the same as if a black would hit and of course the odds that a zero would hit. Just to satisfy the curious, the odds of 21 reds hitting in a row prior to the start of the sequence is 3.73 million to one (European) and 6.52 million to one (American).

The expected return is always negative with any form of fixed odds gambling (apart from expert card counters at Black Jack). For every $100 bet, you should expect to lose $2.7 at European roulette and $5.3 at American roulette over time. If you have short term luck, you should set yourself a target of win or lose and leave when you hit your target. If you win and continue gambling, it is more than likely that the odds will start to take effect. With time, you will most likely lose all your winnings as well as your own money.

There are a myriad of systems and people claiming to have the magic winning system. Some of the most popular systems are listed in the Section Roulette Systems but you can't beat simple mathematics. Mathematics and gambling do not go together as mathematics deal with certainty whilst gambling is all about risk and uncertainty. However, if there was such a thing as a sure winning system, the casinos would not exist and the one who devised the system would most likely keep it to himself. The laws of mathematics clearly state that you can not device a guaranteed winning system for the player when the house has a guaranteed edge on every spin. The best advice is to view roulette as any other form of fixed odds gambling as a leisure time and set a limit of the money that you can "afford" to lose. For example, instead of going out to a nightclub that might have led you to spend $200 in an evening, you can set the limit as $200. If you lose it, then you would in monetary terms be none the worse off than if you had gone to the night club.