If you have an even probability of winning or losing, those are 50-50 odds.
If you want to express probability as a decimal number, it's 0.5.
You are equally likely to get one result as you are the other.
In Las Vegas lingo these odds described as 1 to 1, meaning you have one chance for a desired result to one chance against it.
Or alternatively you might also say that the odds are 1 in 2, meaning 1 chance in 2 tries to win.
Can you see how these different ways of stating the odds can change how math curriculum must be written?
Boy, is it confusing to teach probability.
She and my grandfather had gone to Las Vegas for many, many years, always with a friend who was a REAL gambler. Meaning he got invited to special suites, offered "free" meals, given limousine transportation everywhere, tickets to the sold-out shows. You get the idea.
He had lost BIG TIME (again) and they were cleaning out their things from the hotel room prior to flying back to Iowa. The maid came in the room and said to my grandmother's (weeping) friend,
Take the towels honey, you paid for them. You paid for all the towels in the hotel for the whole year.
I'm in Las Vegas as you are reading this. For a business conference. The story is still in my mind, more than 40 years after I first heard it.
What do you give as the odds that I will be down in the casino gambling? Right! 100/1 I'm not gambling.
I'd rather gamble on something like this - I know I'll lose, but it will be a lot more fun!