Have your cards add up to more than the dealer's cards without going over 21. In blackjack jacks, queens, and kings are all worth 10. Aces can be worth 1 or 11, whichever lets you get a higher score that is less than or equal to 21.
To start a game, you place a bet for your hand, and the dealer deals you 2 cards and themselves 2 cards. You can see both of your cards, but only one of the dealer's cards. You are given a few options of what to do with your hand (none of these require a prefix with the bot):
hit: You get dealt another card, and may choose another option if you have not gone over 21.
stand: Choose to not draw any more cards and compare your hand to the dealer's as it is.
double down: If you have enough money on hand, you can double your bet, but this forces you to hit once and immediately stand.
split: This option is only available when you have two of the same card when dealt your hand. Like doubling down, you must also have enough money on hand since you have to make another bet for the second hand. You will get dealt a second card for each of your two hands, and you get to finish playing for each one separately.
Once you have stood, the dealer draws. The dealer always follows a simple rule: They keep hitting until they have at least 17, then they stand.
If any player goes over 21 while drawing cards, they bust, or automatically lose. Otherwise, the hand with the highest value wins. While 21 is the highest score you can get, not all hands that add up to 21 are the same. If you get an ace, and a card worth 10, that is considered blackjack, and will beat any hand that is not blackjack.
1 / number of symbols ^ 2
To increase the probability of winning, you would remove symbols. To decrease the probability of winning you would add more symbols. The multipliers for each symbol do not affect the probability, however they will affect the overall payouts.
The default probability is 11.1% with 3 symbols, and the highest probability is 100% with 1 symbol.