diff --git a/parser/nodes.h b/parser/nodes.h
index cae46da..978bfd0 100644
--- a/parser/nodes.h
+++ b/parser/nodes.h
@@ -67,16 +67,17 @@ class NumberNode : public Node
         }
         NumberNode(refptr<Node> expr)
         {
-            addChild(expr);
+            m_expr = expr;
             m_direct = false;
         }
         virtual double getNumber()
         {
-            return m_direct ? m_number : m_children[0]->getNumber();
+            return m_direct ? m_number : m_expr->getNumber();
         }
 
     protected:
         double m_number;
+        refptr<Node> m_expr;
         bool m_direct;
 };