In Class 3 (vegas style) gaming, any game that represents a physical game, such as keno, blackjack, poker, etc has to have the same outcomes as if the cards/dice/balls were real. But you are correct for other gaming jurisdictions like Class II gaming, aka video bingo machines in many indian reservations, they select the award first (or really, the bingo game 'plays' in software on a central computer, each gambler's bingo card is auto-daubed, and an award is generated) and then the reels are set to act as if they landed on that winning combination. yes it's been answered to death all ready. The cards and the buttons are just there to make a game out of it. The computer decides if you win or lost the hand. Those types of machines are regulated by a computer system located within the casino. I could literally play with my eyes closed and just hit the button over and over again. I was either going to get paid or not get paid on every hand regardless if I held the cards or not. It produced 5 new cards and the hand paid nothing, but the machine paid me for the straight anyway in the form of a bonus. Instead of holding the straight and hitting the draw button, I held nothing and hit the draw button. With every hand, it's decided if you win or lose when you hit the button. I was playing video poker at an Indian casino in Washington state. Outside of Vegas, some casinos work differently than this. They either hit your numbers or they don't. With Keno it randomly chooses 20 numbers between 1 and 80. Slots favor losing reel spots, where Video poker machines do not favor any one card over another. With slot machines, you don't get an even distribution of symbols. This way, it mimics playing with an actual deck of cards over and over again. Video poker works the same way, but you get an even distribution of all cards in the deck over thousands of cards. When you win, it's because the RNG produced 3 of the same winning symbols that appear on the pay line. Then it's the single bars, then double bars, triple bars and then the higher paying symbols with the highest paying symbol being last.

Next up is the lowest paying symbols such as the cherry. The RNG in a slot machine in Vegas favors losing spots on the reels (spots in between the symbols). It's like that in some casinos, but not in Vegas casinos. It doesn't decide if you win or lose when you hit the button. With slots, the RNG spits out numbers that correspond to reel positions. In Vegas at least, both slot machines and Keno machines work the same way.

How to play keno slots