diff --git a/quiz/exception.html b/quiz/exception.html
index c154b213..c34055e2 100644
--- a/quiz/exception.html
+++ b/quiz/exception.html
@@ -24,7 +24,16 @@ <h1>Error Handling with Array Map</h1>
       // Using map to calculate the square root of each number
       // Use Math.sqrt(number) to calculate sq root
       const squareRoots = numbers.map(number => {
-        return 0
+        try {
+          if(isNaN(number)) throw `${number} is not a valid number`
+          if(number < 0) throw `${number} is negative`
+          return Math.sqrt(number)
+        }
+
+        catch(err) {
+          console.log(`Error: ${err}`)
+          return NaN
+        }
     });
 
       // Displaying the original and transformed arrays
diff --git a/quiz/scripts/map-deep.js b/quiz/scripts/map-deep.js
index e97665e5..d43455c6 100644
--- a/quiz/scripts/map-deep.js
+++ b/quiz/scripts/map-deep.js
@@ -6,7 +6,7 @@ const originalMatrix = [
   ];
   
   const newMatrix = originalMatrix.map((row) => {
-    return row.sort();
+    return Array.from(row).sort();
   });
   
   // Modifying the original matrix (changing the last element of the first row)
diff --git a/quiz/scripts/stack-q1.js b/quiz/scripts/stack-q1.js
index 0d719223..72aa78ea 100644
--- a/quiz/scripts/stack-q1.js
+++ b/quiz/scripts/stack-q1.js
@@ -16,6 +16,14 @@ class PStackImpl extends PStack {
     super();
   }
 
+  get persons() {
+    return this._persons;
+  }
+
+  set persons(persons) {
+    this._persons = persons;
+  }
+
   push(p) {
     return this._persons.push(p)
   }
diff --git a/scripts/exception.js b/scripts/exception.js
index c5e554fa..98582256 100644
--- a/scripts/exception.js
+++ b/scripts/exception.js
@@ -6,7 +6,7 @@ window.onload = function() {
         let x = document.getElementById("demo").value;
         try {
             if(x == "") throw 'empty';
-            if(isNan(x)) throw 'not a number';
+            if(isNaN(x)) throw 'not a number';
             x = Number(x);
             if(x < 5) throw 'too low';
             if(x > 10) throw 'too high';
diff --git a/scripts/math.js b/scripts/math.js
index 75ad0f71..64d0f6c7 100644
--- a/scripts/math.js
+++ b/scripts/math.js
@@ -7,6 +7,5 @@ export function add(a, b) {
   
 // Function to multiply two numbers
 export function multiply(a, b) {
-return a * b;
-}
-  
\ No newline at end of file
+    return a * b;
+}
\ No newline at end of file