Build an equation

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ponmalka
Posts: 1
Joined: Mon Jul 08, 2013 12:58 pm

Build an equation

Post by ponmalka » Mon Jul 08, 2013 1:05 pm

I was thinking about a little Problem. Imagine you write down five digits (0,1,...,9) on piece of paper.
You can now fill the gaps in between the digits with as many of the following symbols as you want:
"+", "-", "*", "/", "^", "(", ")", "="

The question is:
For every possible combination of five digits, is it possible to fill the gaps, so that the result is a legit equation?

If not, would it be possible if you add the squareroot and/or the factorial?

Edit: For example:
8 7 2 1 3 could become this equation: -8 + 7 = 2 - 1 * 3

throwaway
Posts: 1
Joined: Wed Dec 10, 2014 12:39 pm

Re: Build an equation

Post by throwaway » Wed Dec 10, 2014 12:42 pm

I have a solution for 5 digits and the symbols "+", "-", "*" and "/" (but without leading "-" like in "-3+5"
~83% of the combinations of five digits have a solution.

If you add the modulus operator "%", ~99% have a solution.

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