Question 176054
Take any number
{{{z}}}
Square that number and then subtract one. 
{{{z^2-1}}}
Divide by one less than your original number. 
{{{(z^2-1)/(z-1)}}}
Now subtract your original number.
{{{(z^2-1)/(z-1)-z}}}
We can factor {{{z^2-1}}}
{{{z^2-1=(z-1)(z+1)}}}
{{{(z^2-1)/(z-1)-z}}}
{{{((z-1)(z+1))/(z-1)-z}}}
{{{(cross((z-1))(z+1))/cross((z-1))-z}}}
{{{(cross(z)+1)-cross(z)}}}
{{{1}}}
That's how this game worked. 
I leave it to you to come up with your own. 
Working backwards is usually the best way to get the answer.