On Apr 6, 1:53 pm, Carlos <a... / quovadis.com.ar> wrote:
> [Ruby Quiz <j... / grayproductions.net>, 2007-04-06 14.55 CEST]
> [...]
>
> > The NPR show "Car Talk" has regular quizzes that they call "Puzzlers"[1]. The
> > one listed on their web site for March 12th[2] is titled "Getting to 100". In
> > the quiz, you are supposed to write down the digits 1-9 in order, followed by "
> > = 100", and then insert between them two minus symbols and one plus symbol (in
> > any order) to make the formula correct. You aren't allowed to re-arrange digits,
> > or do some toothpick math like combine two minus signs to make a plus. You must
> > use every digit, and all three operators.
>
> Can the plus and minus symbols be used as unary operators?

Not as described, in the original quiz, but I'd say...sure! :) It
would require that it either be applied before the first digit:
  -12345 - 67 + 89
or after another operator:
  123 + -45 -6789
but I don't see any reason to disallow that sort of extra logic if you
want to do it.