pacmandefense

I think of it this way and please correct me or add to this if you feel I'm mistaken. Given the ods of 1 to 4 of something occurring, then the probability is 1/5 or 20% from the definition above. To me '1 to 4' has always meant that out of five you have 1 chance of having 'it' occur. The denominator is the sum of all possible events.