Mathematics
Probability
Quick fact
The probability of an event is always a number between 0 and 1, where 0 means impossible and 1 means certain. For example, the probability of rolling a 7 on a standard six-sided die is 0, while the probability of rolling a number between 1 and 6 is 1.
Why this is interesting
You flip a coin—heads or tails? You know each outcome is equally likely, but how do we actually measure that 'likelihood'? That's the mystery probability helps solve.