Sometimes, probabilities are stated in terms of odds, the ratio of the probability of the event’s occurring to the probability of its not occurring.
Suppose you roll a six-sided die. Find the odds that you roll a number greater than four.
There are two favorable outcomes (5 and 6), and four unfavorable outcomes (1, 2, 3, 4). So the odds are
or "one-to-two odds" that you will roll a number greater than four.