On Mon, 12 Nov 2007 22:14:03 +0100, Thomas Nordhaus <email@example.com> wrote:
>firstname.lastname@example.org schrieb: >> So, using only +, -, x, /, and parentheses, and ONLY these numbers: >> >> 1, 7, 7, 7, 7 >> >> how can you make 100? Is there more than one solution? >> > >How about this: 7+7+7+7+7+7+7+7+7+7+7+7+7+7+1+1. I think, that's the >only solution.
The implication of showing four 7's is that you are supposed to use only those four 7's, and hence, only one 1.
If you allow any number of 7's and 1's, it should be obvious that there are infinitely many solutions.