diff --git a/README.md b/README.md
index caf79e5..d5e7664 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,12 @@
   - divide
 
 # API
-## Add
+
+## Add_Merged_test
+
 * add 사용법
- - add(a, b)
-* sub 사용버
- - sub(a, b)
+  - add(a, b)
+* sub 사용법
+  - sub(a, b)
+* mul 사용법
+  - mul(a, b)
diff --git a/calculator.js b/calculator.js
index 4858716..34eb88d 100644
--- a/calculator.js
+++ b/calculator.js
@@ -12,4 +12,8 @@ const multiply = (a, b) =>{
 
 const divide = (a, b) =>{
     return a / b;
+}
+
+const sqaure = (a, b) =>{
+    return a ** b;
 }
\ No newline at end of file