The maths...
To get every combination of 1 to 9, he'd have to buy 84 tickets, i.e. £84

There's a 1 in 16.85 chance of three of those nine numbers coming up in the draw, and he'd win 20 3-ball prizes (£200).

There's a 1 in 142.29 chance of four of them coming up, and he'd win 40 3-ball prizes (£400), and 10 4-ball prizes.

There's a 1 in 2,840 chance of five of them coming up, and he'd win 40 3-ball prizes (£400), 30 4-ball prizes and 4 5-ball prizes.

There's a 1 in 119,306 chance of five of them coming up and the bonus ball being one of them, and he'd win 40 3-ball prizes (£400), 30 4-ball prizes, 3 5-ball prizes and 1 5-ball plus bonus ball prize.

There's a 1 in 170,438 of six of them coming up but not the bonus ball, and he'd win 20 3-ball prizes (£200), 45 4-ball prizes, 18 5-ball prizes and the jackpot.

There's a 1 in 7,158,382 chance of six of them coming up and the bonus ball being one of them as well, and he'd win 20 3-ball prizes (£200), 45 4-ball prizes, 12 5-ball prizes, 6 5-ball plus bonus ball prizes and the jackpot.

However, there's a 93.33% chance he'll win nothing.
(Vice Admiral Sir Charles Cockbrush KCB MBE DSO, who is finding it increasingly difficult to log into b3ta.com wants to duck your aunt and kick your puppy, Tue 12 May 2009, 11:16, 1 reply)

I think that was how he explained it to me.
It might have been 8 numbers though.
( G/PP 💩💩💩💩💩&#128, Tue 12 May 2009, 11:37, closed)

Sounds more likely
To fully cover eight numbers you need to buy 28 tickets.

I'm not doing all that maths again though!
(Vice Admiral Sir Charles Cockbrush KCB MBE DSO, who is finding it increasingly difficult to log into b3ta.com wants to duck your aunt and kick your puppy, Tue 12 May 2009, 14:18, closed)

I wonder
what the minimum number of tickets is to win at least one prize (i.e. get 3 of the numbers). I could probably work it out but don't care enough :)
(Richy_T hundreds if not thousands of dollars, Tue 12 May 2009, 17:08, closed)

This is a pretty hard problem
I've been thinking about it for ten minutes now and still can't work it out. My feeling is that it's a very, very high number. I'll think about it some more.
( flatfrog Staring vacantly into space, Tue 12 May 2009, 21:16, closed)

I think I got it
You'd have to guarantee 3 numbers out of 6 leaving 3 that don't matter so I reckon every combination of 3 from 46 numbers.

46 * 45 * 44 = £91,080.
( stopmeandslapme Cometh the hour, cometh your mum, Wed 13 May 2009, 8:10, closed)