h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Call me a nerd, but I found this while reading "The Restaurant At The End Of The Universe".

When Arthur, Ford, Trillian, and Zaphod go down to the parking bay of the Restaurant, Marvin tells Arthur and Trillian that he has been waiting for them for 576,000,003,579 years. The digits of this number add up to equal 42!

Coincidence? I think not.

Can anyone else find any?

--------

Anyway here's mine:
U595733

0!+5+sqrt(9)x5+7xsqrt(3x3)

You don't need an extra 0 and sqrt's:
(5-9+5)*7*(3+3)=42

59-5-(7-3)*3
5*9-5-7+3*3
((5+9)/(5-7+3))*3

Okay, how does everyone come up with these so fast? Or do I just suck at these kinds of problems (probably the case...)?

I tend to cheat much of the time - I got bored last year and wrote a program to find them for me. It tries about half a million possible formulas per second, and records the ones that work.

I sift through the results I get out, and try to post a few selected results, either simple ones other people have missed, or elegant ones that would be unlikely to be found.

However, seeing the *kinds* of results that work often has improved my manual skills a little.
For example, if a number starts or ends with a 3, 6 or 7, it's well worth trying to make the rest of the number work out as 14, 7, or 6. That works surprisingly often, and similar common tricks do help with other numbers.

I program in C every once in a while. Is there some way you could send the source to me?

I do it all by hand on a piece of paper. Normally I just try to find a way to make 6*7.

I tend to just do it in my head....

Usually try the same way as Marjin...