Minor grammatical fixes

calculator/calculator.js

@@ -1,13 +1,13 @@
 const add = function() {
-
+	
 }
 
 const subtract = function() {
-
+	
 }
 
 const sum = function() {
-
+	
 }
 
 const multiply = function() {
@@ -15,18 +15,18 @@ const multiply = function() {
 }
 
 const power = function() {
-
+	
 }
 
 const factorial = function() {
-
+	
 }
 
 module.exports = {
-	add,
-	subtract,
-	sum,
-	multiply,
-    power,
-	factorial
+  add,
+  subtract,
+  sum,
+  multiply,
+  power,
+  factorial
 }