Midy's Theorem is a mathematical principle that helps us figure out how likely something is to happen. It says that if something has the same chance of happening no matter how many times you try it, then the chances that it will happen at least once out of a certain number of tries is 100% divided by that number of tries. For example, if you have a 50% chance of winning a lottery, then Midy's Theorem tells us that no matter how many times you play, you have a 100% divided by the number of times you play chance of winning at least once.