diff --git a/mrbgems/mruby-numeric-ext/mrblib/numeric_ext.rb b/mrbgems/mruby-numeric-ext/mrblib/numeric_ext.rb
index e86e8b283..576605cb1 100644
--- a/mrbgems/mruby-numeric-ext/mrblib/numeric_ext.rb
+++ b/mrbgems/mruby-numeric-ext/mrblib/numeric_ext.rb
@@ -1,4 +1,4 @@
-module Integral
+class Numeric
   def zero?
     self == 0
   end