diff --git a/cobertura.xml b/cobertura.xml
index 25702b7..f449c6d 100644
--- a/cobertura.xml
+++ b/cobertura.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE coverage SYSTEM "http://cobertura.sourceforge.net/xml/coverage-04.dtd">
-<coverage line-rate="0.73378839590444" branch-rate="0" lines-covered="2150" lines-valid="2930" branches-covered="0" branches-valid="0" complexity="1321" version="0.4" timestamp="1752264041">
+<coverage line-rate="0.73378839590444" branch-rate="0" lines-covered="2150" lines-valid="2930" branches-covered="0" branches-valid="0" complexity="1321" version="0.4" timestamp="1752353170">
   <sources>
     <source>/home/thomas/projekte/calc/src</source>
   </sources>
diff --git a/src/Engine.php b/src/Engine.php
index 9b74605..fcb5840 100644
--- a/src/Engine.php
+++ b/src/Engine.php
@@ -256,7 +256,7 @@ class Engine
 
     public function calc()
     {
-        $this->calcGraph = new Graph($this->formulas, $this->parameters);
+        $this->calcGraph = new Graph((string) $this->formulas, (string) $this->parameters);
         $this->debugCalcFormel = [];
         $this->debugCalcVariables = [];
         $this->debugFlatPrice = [];
diff --git a/src/Graph/Calc.php b/src/Graph/Calc.php
index bf9cb16..276c90a 100644
--- a/src/Graph/Calc.php
+++ b/src/Graph/Calc.php
@@ -30,7 +30,7 @@ class Calc
             eval($this->params);
             eval($this->formulas);
             if ($y->getParsed() != '') {
-                eval('@$result = ' . $y->getParsed() . ';');
+                eval('$result = ' . $y->getParsed() . ';');
                 $y->setResult($result);
             }
         }