Update quiz.mdx

Author: jrakibi

decoding/quiz.mdx

@@ -137,7 +137,7 @@ Let’s see how well you understand the core concepts of locking and unlocking s
     <div class="flex-grow h-0.5 bg-gradient-to-r from-gray-400 via-orange-300 to-transparent"></div>
 </div>
 
-## Ex 4: Script Success and Failure
+## Ex 3: Script Success and Failure
 
 This quiz will test your understanding of what makes a Bitcoin script valid or invalid, focusing on the conditions that lead to script success or failure.
 
@@ -219,7 +219,7 @@ This quiz will test your understanding of what makes a Bitcoin script valid or i
     <div class="flex-grow h-0.5 bg-gradient-to-r from-gray-400 via-orange-300 to-transparent"></div>
 </div>
 
-## Ex 5: Standard and non-standard transaction
+## Ex 4: Standard and non-standard transaction
 
 Test your knowledge of standard and non-standard scripts, understanding the criteria that Bitcoin nodes use to relay or reject transactions.