Reading "What are bingo rules?" starts with the family it belongs to. Every casino floor carries a few games that are neither cards dealt to a hand nor a wheel with a ball in it. Keno, bingo and scratch cards all work by matching numbers or symbols already decided somewhere else, and casino war sits beside them as the shortest game in the building. They share a shape: the player commits first, and the result arrives in a single step.
Bingo replaces the pick with a printed card and the draw with a caller. Numbers come out one at a time and each player marks a card against them until a pattern completes — a line, two lines, or the full card. A ninety ball game and a seventy five ball game differ in the size of the field and in the patterns that count, which is why the rules sheet carries more than it looks.
Casino war is the card game of childhood with a stake on it. Both sides get one card, the higher wins, and a tie offers either surrender for half or a raise to fight it out. A tie is far commoner here than at a card table, since only the rank matters and suits are ignored. Those tie rules carry the whole game: the raise is the only decision in it, and the house keeps its margin almost entirely from what the matching cards do.
The table of prizes still remaining in a run shows what is actually left to win, which says more than the overall odds on the back.
Every choice comes before the round: how many keno spots to take, which card to buy, or whether to go to war, since the draw itself allows no strategy.
Matching four of five picks is a different prize from matching four of eight, so each spot count gets its own column, and venues can pay quite differently.
A caller draws numbers one at a time, and each player marks them on a printed card until a winning pattern completes.
When both cards match in rank, the player chooses to surrender half the stake or raise and go to war; the house draws most of its margin from ties.
Common winning patterns are a single line, two lines, or the whole card, known as a full house, with the rules sheet naming which ones count.