diff --git a/mrblib/00class.rb b/mrblib/00class.rb
index 39e0d5091..f3762e8d0 100644
--- a/mrblib/00class.rb
+++ b/mrblib/00class.rb
@@ -8,4 +8,19 @@ class Module
   def attr(name)
     attr_reader(name)
   end
+
+  # 15.2.2.4.27
+  def include(*args)
+    args.reverse.each do |m|
+      m.append_features(self)
+      m.included(self)
+    end
+  end
+
+  def prepend(*args)
+    args.reverse.each do |m|
+      m.prepend_features(self)
+      m.prepended(self)
+    end
+  end
 end
diff --git a/src/class.c b/src/class.c
index 0f72c7753..47a6c846b 100644
--- a/src/class.c
+++ b/src/class.c
@@ -947,24 +947,6 @@ mrb_mod_prepend_features(mrb_state *mrb, mrb_value mod)
   return mod;
 }
 
-static mrb_value
-mrb_mod_prepend(mrb_state *mrb, mrb_value klass)
-{
-  mrb_value *argv;
-  mrb_int argc, i;
-
-  mrb_get_args(mrb, "*", &argv, &argc);
-  for (i=0; i<argc; i++) {
-    mrb_check_type(mrb, argv[i], MRB_TT_MODULE);
-  }
-  while (argc--) {
-    mrb_funcall(mrb, argv[argc], "prepend_features", 1, klass);
-    mrb_funcall(mrb, argv[argc], "prepended", 1, klass);
-  }
-
-  return klass;
-}
-
 static mrb_value
 mrb_mod_append_features(mrb_state *mrb, mrb_value mod)
 {
@@ -976,24 +958,6 @@ mrb_mod_append_features(mrb_state *mrb, mrb_value mod)
   return mod;
 }
 
-static mrb_value
-mrb_mod_include(mrb_state *mrb, mrb_value klass)
-{
-  mrb_value *argv;
-  mrb_int argc, i;
-
-  mrb_get_args(mrb, "*", &argv, &argc);
-  for (i=0; i<argc; i++) {
-    mrb_check_type(mrb, argv[i], MRB_TT_MODULE);
-  }
-  while (argc--) {
-    mrb_funcall(mrb, argv[argc], "append_features", 1, klass);
-    mrb_funcall(mrb, argv[argc], "included", 1, klass);
-  }
-
-  return klass;
-}
-
 /* 15.2.2.4.28 */
 /*
  *  call-seq:
@@ -2247,10 +2211,8 @@ mrb_init_class(mrb_state *mrb)
   mrb_define_method(mrb, mod, "class_variable_set",      mrb_mod_cvar_set,         MRB_ARGS_REQ(2)); /* 15.2.2.4.18 */
   mrb_define_method(mrb, mod, "extend_object",           mrb_mod_extend_object,    MRB_ARGS_REQ(1)); /* 15.2.2.4.25 */
   mrb_define_method(mrb, mod, "extended",                mrb_bob_init,             MRB_ARGS_REQ(1)); /* 15.2.2.4.26 */
-  mrb_define_method(mrb, mod, "prepend",                 mrb_mod_prepend,          MRB_ARGS_ANY());
   mrb_define_method(mrb, mod, "prepended",               mrb_bob_init,             MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "prepend_features",        mrb_mod_prepend_features, MRB_ARGS_REQ(1));
-  mrb_define_method(mrb, mod, "include",                 mrb_mod_include,          MRB_ARGS_ANY());  /* 15.2.2.4.27 */
   mrb_define_method(mrb, mod, "include?",                mrb_mod_include_p,        MRB_ARGS_REQ(1)); /* 15.2.2.4.28 */
   mrb_define_method(mrb, mod, "append_features",         mrb_mod_append_features,  MRB_ARGS_REQ(1)); /* 15.2.2.4.10 */
   mrb_define_method(mrb, mod, "class_eval",              mrb_mod_module_eval,      MRB_ARGS_ANY());  /* 15.2.2.4.15 */