[Python, size 15, by mbomb007](http://codegolf.stackexchange.com/a/44494/11006)
=

There are at least 5 permutations that work. This is one of them:

    `3*.7/50`[::~4]

It was pretty obvious that the original code was something of the form `` `«expression»`[«range»]``, so it wasn't difficult to place the backticks, colons and square brackets. On a hunch, I assumed that the range specifier was `[::~i]` for some value of `i`, leaving only 8 characters to permute. This took only a fraction of a second. Here's the code I used:

    from itertools import permutations
    
    perms = [''.join(p) for p in permutations('03457*./')]
    for p in perms:
        try:
            e = '`'+p[:-1]+'`[::~'+p[-1:]+']'
            if eval(e)=='6991':
                print e
        except:
            continue

(The original code is actually a bit flakey, since the result of `3*.7/50` isn't guaranteed to be `0.041999999999999996` all of the time.)