I'll help you with math, but I don't think math is your problem. You just need to understand the lingo.
BLUE said:
2 6 to 5 favorite 20%
7 4 to 3 " 33%
10 7 to 5 underdog -140%
A 2 to 1 " -200%
A 6-to-5 favorite has a 6/11 chance of winning and a 5/11 chance of losing. His edge, or expected value, is +1/11 (+9%), and his chances of winning are 20% higher than his chances of losing. A money line bet might be expressed as -120, or that one would have to put down $120 to win $100.
A 2-to-1 underdog has a 1/3 chance of winning and a 2/3 chance of losing. His edge, or expected value, is -1/3 (-33%), and his chances of winning are 50% lower than his chances of losing. A money line bet might be expressed as +300, or that one would win $300 if $100 were risked.