php calculate formula in string [duplicate]

Answer 1

Take a look at

http://www.phpclasses.org/package/2695-PHP-Safely-evaluate-mathematical-expressions.html

Which can evaluate Math Code

 // instantiate a new EvalMath
  $m = new EvalMath;
  $m->suppress_errors = true;
 // set the value of x
  $m->evaluate('x = 3');
   var_dump($m->evaluate('y = (x > 5)'));

Found at: Process mathematical equations in php