In the case of sport betting it is more of an instinct than a mathematical calculation. It is almost impossible to find a pattern. If you watch football a lot like I do it is easier to find a good bet, and thus win more times than you lose in a large number of bets. But that goes for how well you know the teams, form, injuries etc and not mathematical calculations. Anyways professional betters have a winning percentage of as high as 90% so they don't do the numbers game like you said relying on the 5% to make them money, THEY know football!

Just curious, but what makes you think all that? Not trying to diss or anything, but it sounds like that's something you just assume, b/c you've been told they win 90% and 'know' the game. It's simply not true...and those who are telling people they make 90% a year are usually scams that make a living by ppl who fall for their stuff...

Look at those links:

http://www.windersports.net/winningpercentages.htm
http://www.sportsinsights.com/sportsbettingresources.asp
http://professionalgambler.com/Winperct.html
http://www.sportsinsights.com/sportsbooks/si_suggested.asp
They are the first 4 links that show up when I google for "Professional sports bettors" and "winning percentages" and in every one it says something along the lines "people usually believe pro bettors sustain a very high winning percentage, but they only win 55-58/60% of their bets usually".

I've read a whole lot of stuff about this topic and believe me they do use mathematical formulas..one quote by one of the most successful baseball bettors:

"Here are many of the factors that I consider, and a rough idea of how I go about evaluating all these considerations in relation to any game to be played.

For my MONEY LINE I look at teams and pitchers separately. I begin by closely estimating a team's percentage chance of winning a game by evaluating that team's overall statistics compared to those of its opponent. In doing so I look mainly at the following areas of performance: Win/loss record overall, W/L home and away, W/L against Right and Left hand pitching, day and night, grass and turf, and batting performance I look at each team's last 10 games, whether or not they are in a losing or winning streak, their position in the home and road schedule, the ball park (its nature and dimensions). I consider the weather, the umpires (plate umpires), and lineups I have a very strong way of factoring in runs scored/runs allowed percentages, and much, much more.

The other half of the game, pitching, I handicap separate from the teams. In pitching I consider the starting pitcher's overall performance, his recent performance and his general performance over a period of time, also as per the ball park in which he'll be pitching. I determine what percentage of the game he'll be pitching and multiply that number by the final ERA number I assess to him. I then combine this number with that part of the bullpen and its contribution that will most likely act as his relief. Next I add the starter and the bullpen factors together for a final pitching factor for each team.

Next, I take my final team factor and mathematically combine it with that team's pitching factor for the game I do this for both the home and away teams, and then compare these on a relative basis. For example, the home team might end up with a composite factor of 300, while the visiting team might end up with a composite factor of 200. Dividing the larger factor (the proposed favorite) by the smaller gives me a money line. In this example that would be 300 divided by 200 equals 1.5. This equates to the favorite being $1.50 on a true, no juice line.

Simple, but a lot of work. Accurate! Well, it usually makes me a net of up to 10 cents on the dollar at season's end. "

They really do use mathematical or rather statistical formulas..they apply statistics (which is part of applied maths) to be able to predict probabilities, thus they can tell which of the bets they consider have a winning percentage of 55% or over...and that way...by placing enough bets, they do make money that way.

The tricky part is that, of course they could have a somewhat higher winning percentage than 55-60%. Maybe even 70%. That way however they'd place maybe 200 bets per year, but by using all bets that have a higher chance of winning than just 55% they can place around 2,000 - 3,000 bets per year. And by placing 2,000 or 3,000 bets each year they make gains of around 100% though really just having a winning percentage of say 57%.

That allows them to turn their cash over WAY more often and they make a lot of money.

However, I don't plan on becoming rich betting on sports or suggest anyone on here does, as I don't know enough about that thing and b/c it seems to me that being able to become successful in the world of sports betting (c-o-n-s-t-a-n-t-l-y) is even WAY harder to pull of than being successful trading stocks/currencies/etc. (even though that isn't exactly easy either...)

But, I think one can learn a great deal from pro sports bettors:

- wise money management (they always place the same amount of cash on every bet and never place more than 1% per bet, to minimize their risk)

- they have an approach, that works. That way they don't depend on luck, b/c they don't care too much whether they lose some money on one day and dont overrate winning some money on the next day, b/c if their system is working, which they can find out by using the right simulation tools, then it's working and they WILL make money in the long run.

..and those 2 things are important at the stock market, too, whether you're a trader or a long term investor...you don't put all your money on one stock, b/c that would mean depending on luck and taking a high risk...in other words you'd be gambling.

..and you do need to have an approach that's working. Without having one that's proven to work, there's no point in trading (or investing in) the market!