We have a 'fifty-fifty' chance of succeeding. [=we are as likely to succeed as we are to fail]
The bill for dinner came to $43, and she gave him a 'fifty'.
They divided/split the expenses 'fifty-fifty'. [='equally']
(..) What's going on? Hal, what happened? I think a bee flew up my nose. I was just about to make my frontal assault to rescue you, when like fifty ninjas tried to attack me. So I had to beat them all up, and I did... - and they were all like crying, so. - Wow. Brave one, isn't he. Who are you? (..)2010 Megamind