Question 171505
First thing:  Please stop posting in all CAPS.  It is the electronic equivalent of shouting and therefore rude, insensitive, and annoying.


Your equation is actually missing an element.  One could reasonably ask "10% of what?" because it isn't specified.  In practical terms, I would just assume that you mean some value x minus 10% <i>of that same value x</i> is equal to 180 -- symbolically speaking:


{{{x-0.10x=180}}}


Now your problem is a simple matter of combining like terms and then dividing by the coefficient on x:


{{{x-0.10x=180}}}


{{{0.9x=180}}} (because {{{1-0.1=0.9}}})


{{{x=180/0.9=200}}}


Hope that helps