It is all about prediction. No fixed formula or methodology is there to calculate the winning number or color. Each spin is independent from the previous outcome and have no effect on the next spin.
There is no memory a spanning wheel. No rules and regulation that white ball follows. No one no there the ball will fall. As it is game of predilection still player follow few strategies. Out of them 2 are popular (1) Grand Martingale system : and (2) Martingale system.
Grand Martingale System : This system target the higher profit each time player loose he double the bet amount i.e. add the original bet amount to it. For e.g. if 25 betted and player lost. Next time he will bet $50 and odd $25 to it and bet amount will be then he recorder $25 originally lost and net gain of $50.
The Martingale System : According to this there cannot be a continuous long. After some losses there will be win. The system says double the amount of bet each time you loss until you win and if you will you cover whole of the already betted amount and gain. extra money for e.g. you bet $25 and lost. Now bet to $50. Then lost again bet to $100. you win your lost on $75 is covered up and $25 in your gain.

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