Poker is a family of card games in which players wager over which hand is best according to that specific game's rules in ways similar to these rankings . While the earliest known form of the game was played with just 20 cards, today it is usually played with a standard deck , although countries where short packs are common, may play with 32, 40 or 48 cards. [1] Thus poker games vary in deck configuration, the number of cards in play, the number dealt face up or face down, and the number shared by all players , but all have rules that involve one or more rounds of betting.