The '''probability''' of an event is typically expressed as the percentage of ways it might happen, out of a number of possible events. The chance of a tossed coin coming up heads is 50%, because there is 1 way it can happen, out of 2 possible ways. 1 / 2 = 0.5 or 50 percent. | The '''probability''' of an event is typically expressed as the percentage of ways it might happen, out of a number of possible events. The chance of a tossed coin coming up heads is 50%, because there is 1 way it can happen, out of 2 possible ways. 1 / 2 = 0.5 or 50 percent. |