A relatively short article on the mathematics of gambling.
Let's say, for example, you want to bet on one of the highlights of the British sporting calendar, the annual university boat race between old rivals Oxford and Cambridge. One bookie is offering 3 to 1 on Cambridge to win and 1 to 4 on Oxford. But a second bookie disagrees and has Cambridge evens (1 to 1) and Oxford at 1 to 2.
Each bookie has looked after his own back, ensuring that it is impossible for you to bet on both Oxford and Cambridge with him and make a profit regardless of the result. However, if you spread your bets between the two bookies, it is possible to guarantee success (see diagram, for details). Having done the calculations, you place £37.50 on Cambridge with bookie 1 and £100 on Oxford with bookie 2. Whatever the result you make a profit of £12.50.
I say relatively because there are literally millions of pages on the web just about blackjack statistics. For instance, it's easy to see how you'll lose money playing blackjack in the long run -- card counting aside -- by looking at this house edge calculator. The only real advantage to the player occurs with a one-deck shoe and a bunch of other pro-player rules, which I imagine are difficult to find at the casinos. (via big contrarian)