A thin opening or groove in something, such as a mail slot in a door. Also called slit, slot, and slotted hole.

Casino slot machines are more popular than table games for a reason — they’re easy to play, offer huge lifestyle-changing jackpots and don’t require splitting a bill with card sharks. But how exactly do they work? And how can you maximize your chances of winning them?

In a traditional mechanical machine, the reels are activated by inserting cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode. Once the reels stop spinning, the symbols must be read to determine whether the player won or lost. Depending on the machine, this can be done either by reading the symbols directly or, as in more modern electrical machines, by interpreting a sequence of signals that the machine sends out when the reels stop rotating (such as a light flashing to indicate service needed).

The modern random number generator, or RNG, that all modern slot machines use operates continuously, running through dozens of numbers per second. When it receives a signal — anything from the button being pushed to the handle being pulled — it sets one of these numbers, which then corresponds with the combination that causes the reels to stop. If you see someone win a big jackpot, don’t be too upset if you didn’t get the same split-second timing: The odds are overwhelming that you would have left the machine before the winner did.