Added article and video for What is the difference between "let," "const," and "var" when declaring variables.

Author: devmamunur

README.md

@@ -344,7 +344,25 @@
 
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-9. What is the difference between "let," "const," and "var" when declaring variables.
+### 9. What is the difference between "let," "const," and "var" when declaring variables.
+<details>
+<summary><b>Answer</b></summary>
+
+
+#### Articles
+- 📜 [var, let, and const in JavaScript – the Differences Between These Keywords Explained](https://www.freecodecamp.org/news/differences-between-var-let-const-javascript/)
+- 📜 [Difference between var, let and const keywords in JavaScript](https://www.geeksforgeeks.org/difference-between-var-let-and-const-keywords-in-javascript/)
+
+
+#### Videos
+- 🎬 [JavaScript Let vs Var vs Constant](https://youtu.be/XgSjoHgy3Rk?si=s-LGJ718BqqDV6E7)
+- 🎬 [let & const in JS 🔥Temporal Dead Zone](https://youtu.be/BNC6slYCj50?si=-O8qYF50913QkyuD)
+- 🎬 [Differences Between Var, Let, and Const](https://youtu.be/9WIJQDvt4Us?si=Mdd-PfA2nN_7P74-)
+
+</details>
+
+---
+
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