Buy 13,983,816 tickets for tonight's pounds 34m rollover draw and you are guaranteed to win the jackpot. Nearly 14 million one-pound stakes allows you to cover every possible outcome from 1-2-3-4-5-6 to 44-45-46- 47-48-49. The winning combination is guaranteed to be one of these sequences - or something in between. Around one hundred million attempts will be made to win the pounds 35m jackpot tonight, so seven joint winners can be expected. Investing 14 million quid to get just five million back is foolish, making the organisers' attempts to foil bids that cover all the bases all the more baffling.

Anyone backing all the horses in a betting shop this afternoon will get at least one prediction right: lottery players are mug punters. Back every horse in the King George VI Chase at Sandown Park this afternoon, and you will get back most of your stake; but on the lottery, less than half your "investment" is returned as prize money. So the National Lottery fails in the first principle of gambling: you should lose money, but slowly. After a triumphant debut in Ladbrokes on the eve of the first 1974 election, with a florin on Labour (3-1 outsiders), I have been on a cheerful downward spiral. A bet buys entertainment, and as such can be excellent value.

Las Vegas exists not because of an American addiction to cash, but because it is a great place to spin out $100 with a hundred spins of the slots or the roulette wheel. A well-run casino is more than a place to lose or win money - it is a magnificent piece of theatre. By comparison, tonight's National Lottery Live is unlikely to be great television. It will, for the 14th month, provide massive prime-time publicity for a private company, and restate the principle that mug gambling is good for you.

Bah - New Year humbug, you could riposte. What about the good causes, starting with your local newsagent? He or she stands to make pounds 700,000 from your pounds 14m flutter, exacerbating the differences between the haves and have-nots: a National Lottery terminal in your shop is a licence to print money. As well as today's commission windfall, retailers enjoy a constant cashflow from insiduous Instants. "Get addicted to gambling in an Instants" should be the text of the scratch card campaign.

The National Heritage Secretary has praised this week's orgy of gambling greed as of great benefit to good causes. But if your reason for playing the lottery is truly altruistic, then your money will work four times harder if you hand it direct to charity.

No: the only national benefit of the National Lottery is to sharpen up our numeracy. To be a sensible investor in the lottery you need to know the three Rs: Reading the rollover forecast, wRiting out the ticket and working out the aRithmetic of probability. You might have thought you left unpleasant expressions such as 49!/(43! x 6!) behind at about the same time as Maths GCSE. You no doubt wondered what possible use those factorials might be. "6!" is not the number of free flights around America that the lottery regulator took courtesy of a Camelot shareholder, but "six factorial": 6 x 5 x 4 x 3 x 2 x 1, or 720. Calculate 43! (the number of non-winning numbers), multiply them together and use this to divide 49! and you get exactly the number of pounds you need to "invest". And if you don't believe me, save your pounds 13,983,816 and spend a fiver on a calculator. Good luck.

Lucky Lottery numbers, page 24