Odds and Probability are frequently misunderstood. Suppose you want to know the chances of rolling an eight with a pair of dice. There are five ways to make an eight out of 36 possible outcomes, so the odds of rolling an eight are 5 in 36. Conversely, the odds against an eight are 31-to-5. The probability of an eight is 5 + 36 = 0.1389.
