diff --git a/calculator/calculator.js b/calculator/calculator.js
index d45cc64..994b75b 100644
--- a/calculator/calculator.js
+++ b/calculator/calculator.js
@@ -23,9 +23,7 @@ const power = function(a, b) {
 const factorial = function(n) {
   if (n === 0) return 1;
   let product = 1;
-  for (let i = n; i > 0; i--) {
-    product *= i;
-  }
+  for (n; n > 0; n--) product *= n;
   return product;
 };