In other words, given odds of (x:y) we can scale it by any positive number alpha to get equivalent odds of (alphax:alphay). When there are only two terms x and y in a set of odds, the odds can be written as a ratio fracxy. It is understood that the odds ratio fracxy refers to the odds (x:y), or, equivalently, left(fracxy:1right).
The x/y notation is confusing - these ratios aren't probabilities are they?