Probability has to do with how likely something is to happen. If there's a 50/50 chance, then the probability is 50%.
Probability is a part of math involving percentages and chance. The probability of a thing happening is the same as the odds or chances of something happening. When you watch a weather forecast, it might say there's a 30% chance of showers; that's probability. Gambling — on sports or something else — is also based on probability. Since most things in life are uncertain, it's helpful to know if the probability is high or low for things you want to do or try.