A more thorough explanation:

A percentage game is a type of game of chance where the house collects a percentage of the wagers made or the sums won. This means that the more people play, the more money the house makes. However, percentage games are illegal in many states.

• Slot machines: Players insert money into the machine and spin the reels. If the symbols line up, the player wins a prize. The house collects a percentage of the money wagered on the machine.
• Bingo: Players buy cards with numbers on them and try to match the numbers called out by the caller. The house collects a percentage of the money spent on the cards.
• Casino games: Games like blackjack, roulette, and craps are also percentage games. The house collects a percentage of the money wagered on each game.

These examples illustrate how the house always has an advantage in percentage games. Even if a player wins a prize, the house still makes money from the percentage they collect on all the wagers made. This is why percentage games are often regulated or illegal in many states.