Update README.md

README.md

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 # Formula1
-**Simple Mathematical formulas evaluator for PHP**
+##Simple Mathematical formulas evaluator for PHP
 
 If you need to evaluate a formula with basic operators and variables, and
 
-- You dont want to use EVAL for obvious security reasons
-- You don't want to rely on half the internet as dependancies, but prefer a single self-contained class
-- You don't necessarily have the latest PHP version
-- You want something readable that you could easily understand and customize.
+- You dont want to use EVAL for obvious security reasons,
+- You don't want to rely on half the internet as dependancies, but prefer a single self-contained class,
+- You don't necessarily have the latest PHP version,
+- You want something readable that you could easily understand and customize,
 
 Then you might like Formula1 ! ;-)
+
+
+**Simple usage no variables**
+$f1 = new Formula1('-45+(41*2)-(6/(3+1))');
+echo($f1->compute()); // 35.5
+
+**Simple usage with variables**
+$f1 = new Formula1('-45+(fourty_one*2)-(6/(three+1))' , ['fourty_one'=>41, 'three'=>3]);
+echo($f1->compute());
+
+**Funky usage with variables that include formulas themselves (and recusrively)**
+$f1 = new Formula1('-45+(fourty_one*2)-(6/(three+1))' , ['fourty_one'=>'82/2', 'three'=>'12/four', 'four'=>4]);
+echo($f1->compute());
+
+
+