Slots are complex machines with a smart computer that controls them. All slot machines work by using a Random Number Generator (RNG), which continuously generates a massive amount of numbers. When you hit the spin button, the RNG determines whether you'll win or lose, making it impossible to predict the outcome.
To see how one slot works and how cost-effective it is, we use the RTP rate. The Return To Player (RTP) is expressed as a percentage and shows us how much the player is paid back over a lengthy period by the slot machine. Slot machines with an RTP of 97%, for instance, will pay out C$97 for every C$100 wagered.
Also, RTP is very easy to calculate, and you can calculate it by yourself. You simply need to pay a certain amount of money, and after more spin on the slot, see what percentage of the initial amount you have left. Of course, the higher the number of slot rotations, the more accurate your calculation is.