diff --git a/README.md b/README.md
index 8cd51ba..99059e8 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 **PRO**cessor of **L**ist for Mathematical Calculation
 
-It's a simple minimal lisp interpreter written by ruby.
+It's a simple minimal lisp interpreter written in ruby.
 
 ![](./screenshot/demo.svg)
 
diff --git a/prol.rb b/prol.rb
index 54172a2..c33be1f 100644
--- a/prol.rb
+++ b/prol.rb
@@ -50,7 +50,7 @@ module Lisp
 
   def self.make_global
     @global_env ||= begin
-      ops = %i[== != < <= > >= + - * /]
+      ops = %i[== != < <= > >= + - * / % & | ^ ～]
       ops.inject({}) do |scope, op|
         scope.merge op => ->(*args) { args.inject(&op) }
       end