One conceivable strategy would be to bet on red for a certain number of spins, for example, 38.
There are 18 red squares on a roulette board out of 38 squares in total. Dividing 18 by 38 gives the probability that red will come out, which is 47.37%. This probability can be used in a binomial distribution and transformed into an approximate standard normal distribution.
This operation indicates that if we turned the wheel 38 times, the probability that the ball will stop on red at least 10 times is 99%. The probability, out of 38 strokes, that the ball will land on red at least 15 times is 83%. Over 38 laps, there is a 50% chance that 18 reds will come out.
However, the critical point is 19 moves, since the bet on red is 1/1, and the probability of 19 red coming out on 38 moves is only 37%. This shows the difficulty of winning by betting only on red.
The results happen because, as equation 18 divided by 38 equals 47.37% shows, the ball will land on red less than half of the time. This percentage applied to the binomial and standard normal distributions creates the great gap in terms of the probability between 18 red spins and 19 out of 38 red spins. It is very unlikely for anyone to get more than 18 red spins out of 38 spins.
Use the dozen bet
There are two versions of this system, the single dozen bets and the double dozen bets. In the single dozen version of the bet, the player uses a gradually increasing bet list starting at the casino table minimum and going up to the table maximum. The objective here is to use a single dozen bet to win before the betting list ends. Many techniques are employed such as: betting that the same dozen will come out after two consecutive appearances, betting on the dozen that appeared the most in the last 15, 9 or 5 moves, betting that the dozen which, after a long absence of 7 turns or more, appears for the first time.
Strategy of the 1st and 3rd column
A 2 chip bet on the 1st column and a 2 chip bet on the 3rd column cover the majority of the red numbers on the table. A bet of 2 chips on black will provide insurance in the event of a black number coming out. This betting system covers almost all numbers except 4 red numbers in the middle column and zero (and double zero in American roulette). If the result is a red number in the 1st or 3rd column, the player breaks even. If the result is red in the middle column, the player loses 6 tokens. If the result is black in the middle column, the player loses 2 tokens. If the result is black in the 1st and 3rd columns, the player only wins 4 tokens.
There are certain roulette strategies that take a more mechanical technique to beat the casino. The most famous is the bias wheel attack. In the biased wheel attack, the player times the wheel to determine statistical deviations indicating certain wheel faults. Since the wheel is made by a human being, it is almost impossible for the roulette wheel to be perfect. The biased wheel attack looks for imperfect wheels and exploits the fact that some wheels will roll numbers more often than 1 in 35, which means it is possible to have an edge over the casino. Timing the wheel involves recording the results of the laps in large numbers in order to identify any opportunities.