Some keno players utilize the strategy of playing the 20 numbers that were drawn on the previous game, changing their numbers each game as circumstances dictate.
As a player myself, I tend to like this kind of strategy, rather than one of always playing the same numbers. For one, I won’t find myself looking at a board one day when I’m not playing, and see all "my numbers" up solid! For another, if for some reason "my numbers" are not coming up, I won’t be stuck on a particular set of numbers.
By using the approach of changing numbers every game (called "Chasing the Dragon" by traditional Chinese players), I at least will not sink below the expected return guaranteed me by the laws of probability.
If you include the last 20 numbers drawn as the basis of your strategy, the odds against "repeaters," numbers that come up two games in a row, are the same as playing a 20-spot ticket. Here are the corresponding odds for a 20-spot ticket:
The average number of repeaters on a 20-spot ticket is five, but this happens only about once every four games. Obviously, if you are lucky and the number of repeaters is six or more, your odds of winning something good are vastly increased, while you face insurmountable odds on those unfortunate draws which are less than five. By looking at the odds above, you can see that draws of 6, 7, 8, and 9 repeaters are quite common, while draws of 10 through 14 are not inconceivable.
How can one employ such a strategy? If you like 10-spot ways, simply line off the last 20 numbers drawn into four groups of five, and play a 6-way-10 spot. (This ticket also has a 4-way-5 and a 4-way-15.)
Do you like 9-spots? Group the 20 into 4 groups of 3 and 4 groups of 2, which will give you a 20-way-9 spot, as well as a 10-way-6. You can play an 8-spot way by dividing the 20-spots into 5 groups of 4, which will give you a 10-way-8. One of my favorite 6-way tickets is 3 groups of 4 and four groups of 2, which constructs a 16-way-6.
The point is, you will gain in your chances of a win when more numbers repeat, and in return, you’ll pay the piper when fewer numbers repeat. That’s why they call it gambling!