Betting calculation always depend on proposition bet. This is my personal experience. Once I had bet $4.93 on a three-team parlay, laying odds of 7 to 5 on the first team, and taking odds of 9 to 5 and 6 to 5 on the other two teams. (Remember, when you lay odds of 6 to 5, you are betting $6 to win $5, or some multiple of these figures. When you take odds of 6 to 5, you are betting $5 to win $6, of some multiple.) The proposition bet was that if the bookie could figure the correct payoff price of the parlay to the first two decimal places, I would pay him that amount. If he failed he would pay me the correct sum. And he paid me also.