When a player presses the spin button, the machine chooses a number that matches a particular combination of symbols on the reels from among the thousands of numbers the RNG generates every second. Arummy circle apklong with random number generators (RNGs), slot machines also have Return to Player (RTP) percentages, which show how much money a player can anticipate winning back on average over time. For example, a machine with a 95 percent RTP should theoretically pay out $95 for every $100 wagered. However, since it is calculated over a long period of time, this figure does not guarantee specific results.