diff --git a/src/Hassium/Interpreter/Interpreter.cs b/src/Hassium/Interpreter/Interpreter.cs
index 2b5a94e..5734f87 100644
--- a/src/Hassium/Interpreter/Interpreter.cs
+++ b/src/Hassium/Interpreter/Interpreter.cs
@@ -921,10 +921,10 @@ public object Accept(MentalNode node)
             switch (mnode.OpType)
             {
                 case "++":
-                    SetVariable(mnode.Name, Convert.ToDouble((object)GetVariable(mnode.Name, mnode)) + 1, mnode);
+                    SetVariable(mnode.Name, Convert.ToInt32((object)GetVariable(mnode.Name, mnode)) + 1, mnode);
                     break;
                 case "--":
-                    SetVariable(mnode.Name, Convert.ToDouble((object)GetVariable(mnode.Name, mnode)) - 1, mnode);
+                    SetVariable(mnode.Name, Convert.ToInt32((object)GetVariable(mnode.Name, mnode)) - 1, mnode);
                     break;
                 default:
                     throw new ParseException("Unknown operation " + mnode.OpType, mnode);