diff --git a/README.md b/README.md
index 5073a91..1410002 100755
--- a/README.md
+++ b/README.md
@@ -153,6 +153,7 @@ duplicate([1,2,3,4,5]); // [1,2,3,4,5,1,2,3,4,5]
 * What is event loop?
   * What is the difference between call stack and task queue?
 * Explain the differences on the usage of `foo` between `function foo() {}` and `var foo = function() {}`
+* What are the differences between variables created using `let`, `var` or `const`?
 
 #### Testing Questions: