diff --git a/ChangeLog b/ChangeLog
index 67761069d1..9380cb7ee0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Oct 27 21:20:35 2009  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
+
+	* ext/tk/lib/tk/variable.rb: add TkVariable#+@ and -@ method.
+
 Tue Oct 27 16:36:52 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (chopped_length): get rid of unexpected exception.
diff --git a/ext/tk/lib/tk/variable.rb b/ext/tk/lib/tk/variable.rb
index 6a618e7ee8..f6ebe551fb 100644
--- a/ext/tk/lib/tk/variable.rb
+++ b/ext/tk/lib/tk/variable.rb
@@ -1175,6 +1175,13 @@ end
     end
   end
 
+  def +@
+    self.numeric
+  end
+  def -@
+    -(self.numeric)
+  end
+
   def &(other)
     if other.kind_of?(Array)
       self.to_a & other.to_a