Sentence:  Whatever you throw is your "chance". I called five for the main, which is the "out" chance, and threw seven to it, which is the "in" chance. If I throw five first, I lose, and if seven I win. You can back me in by betting the odds, or you can <WSD>back</WSD> me <WSD>out</WSD>, by taking the odds, the bank answers either way. 
Meaning of the word marked with <WSD> tags:  To bet on someone losing.