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The idea is this. To start with, you will choose an envelope at random, say by tossing a coin, and look at its contents, which is a cheque for some number  say n. (By randomising like this, you can be sure I haven't subconsciously induced you to prefer one envelope or the other.) You want to make sure that the bigger the number is, the more likely you are to keep it, in other words, the less likely you are to swap. 
There are many sorts of games played in a "bunco booth", where a trickster or sleightofhand expert tries to relieve you of your money by getting you to place bets  on which cup the ball is under, for instance, or where the queen of spades is. Lots of these games can be analysed using probability theory, and it soon becomes obvious that the games are tipped heavily in favour of the trickster! 
Why can't human beings walk as fast as they run? And why do we prefer to break into a run rather than walk above a certain speed? Using mathematical modelling, R. McNeill Alexander finds some answers.

Arguably, the exponential function crops up more than any other when using mathematics to describe the physical world. In the first of two articles on physical phenomena which obey exponential laws, Ian Garbett discusses light attenuation  the way in which light decreases in intensity as it passes through a medium.

Last October, two mathematicians won £1m when it was revealed that they were the first to solve the Eternity jigsaw puzzle. It had taken them six months and a generous helping of mathematical analysis. Mark Wainwright meets the pair and finds out how they did it.

John Haigh takes the above quote as the epigraph for "Taking Chances", and makes his own significant contribution to scientific literacy. He concerns himself with "games of chance" in the broadest sense, from the National Lottery, quiz shows, casino games and card, dice and coin games, through gametheoretic "games" such as military conflicts, to all types of sports.
