

The game of KENO uses 80 balls numbered 1 thru 80. Every game, the house draws 20 balls at random and displays their numbers on screens (called KENO boards) located throughout the casino. The object of the game is for you the player to guess some of the numbers the house will draw.
You make your guesses by marking a KENO ticket, a piece of paper with the numbers 1 thru 80 printed on it. KENO tickets are located at tables throughout the casino but are most readily found in the casino's KENO lounge: a room or area with chairs to sit and write. Usually crayons are provided for marking the ticket.
Before you go marking a ticket you need to decide how much money you want to gamble on the ticket. Near any stash of tickets you are likely to find several copies of the house's KENO brochure, which tells you what the standard bets and payouts are this year. At any point in time all casinos tend to have similar betting/payoff scales, but sometimes there are various "house specials" available. For the sake of simplicity, let's assume for right now you avoid "specials".
Here is what an extract from a KENO brochure might look like.
Play 6 numbers
Catch play $1 play $2 play $5
3 $ 1 $ 2 $ 5
4 $ 8 $ 16 $ 40
5 $ 50 $ 100 $ 250
6 $ 1500 $ 3000 $ 7500
The top line, "Play 6 numbers" means this section of the brochure pertains to the payoffs you would be paid if you marked 6 numbers. "Numbers" are also referred to as "spots". If you play 6 numbers you are said to be "playing a 6-spot". You can play more or fewer than 6 spots but for now let's stick with 6.
The term catch refers to how many of your (6 in this case) chosen numbers match what the house draws. The term "play $1" means you can bet $1 on your ticket. As the table shows, you can bet more than $1 if you're in a real hurry to lose your money. There is no per cent advantage to betting more than the minimum; payoffs are simply scaled by the amount you bet. (In certain -rare- cases your return actually decreases when you increase your bet because the house has an upper limit of how much money per game they will pay off, independent of amount wagered.)
As the payoff table shows, if you play 6 numbers and catch all 6, a $1 ticket will return $1500. What are the odds of this event? A bit over 7500 to 1, as we will see in a later section. It does happen, but not often. (Mrs. Mello, across the street from me when I was in high school, hit a 6-spot in Reno one weekend.)
If you "only" catch 5 numbers the payoff is substantially less, and so on, down to a $1 payoff for catching any 3 of the 6 you selected. If you catch fewer than 3, your ticket is worthless. Of course this is just an example of a payoff schedule; that's why you need to check the KENO brochure to see what payoff scale the casino is using. A later section shows how to calculate the odds.
Note that this payoff is on a "for" basis rather than a "to" basis. Meaning if you collect, say, $8 for matching 4 numbers above, you've already paid $1 for the ticket so you're only "winning" $7. Nevertheless it is standard KENO terminology to say you "won $8".
You can mark a ticket with anywhere from 1 to 15 (more in some places) numbers. The more numbers you mark the more you have to catch to win. The payoffs are set such that in dollar terms the house percentage is pretty much the same regardless of how many numbers you mark. You will find some variety in the minimum payoff so you can to some extent choose if you want many small wins or fewer, larger wins.
Sometimes when you mark a lot of numbers the casino pays off if you catch 0. This would be shown in the KENO brochure.
KEN0 Gambling is the game of choice for me. Cheap and easy to play and gives me the most excitment, UK.