Probability is the measure of the likelihood that an event will occur. Probability is quantified as a number between 0 and 1, where, loosely speaking, 0 indicates impossibility and 1 indicates certainty. The higher the probability of an event, the more likely it is that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written as 0.5 or 50%). To make games random, we use probability to change the game outcome and experience.
The use of dice, spinners, and sand timers adds randomness and conflicts to the game. Limiting the time you have to make a move, limiting your moves to the number you roll on dice, or landing on a certain cell when using a spinner, make the game experience more unique and unpredictable.
Click on the spinner and the coin.