diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js
index e24ecb8e1..69932ca6d 100644
--- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js
+++ b/Sprint-1/3-mandatory-interpret/1-percentage-change.js
@@ -2,7 +2,7 @@ let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ,""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
diff --git a/Sprint-3/1-key-implement/1-get-angle-type.js b/Sprint-3/1-key-implement/1-get-angle-type.js
index 08d1f0cba..9d8411b25 100644
--- a/Sprint-3/1-key-implement/1-get-angle-type.js
+++ b/Sprint-3/1-key-implement/1-get-angle-type.js
@@ -34,23 +34,35 @@ const right = getAngleType(90);
 assertEquals(right, "Right angle");
 
 // Case 2: Identify Acute Angles:
-// When the angle is less than 90 degrees,
+// When the angle is less than 90 degrees,Add commentMore actions
 // Then the function should return "Acute angle"
-const acute = getAngleType(45);
-assertEquals(acute, "Acute angle");
+
+test("should identify acute angles (e.g., 45°)", () => {
+    expect(getAngleType(45)).toEqual("Acute angle");
+    expect(getAngleType(89.9)).toEqual("Acute angle");
+}); 
 
 // Case 3: Identify Obtuse Angles:
 // When the angle is greater than 90 degrees and less than 180 degrees,
 // Then the function should return "Obtuse angle"
-const obtuse = getAngleType(120);
-// ====> write your test here, and then add a line to pass the test in the function above
+
+test("should identify obtuse angles (e.g., 90.1° and 179.9°)", () => {
+    expect(getAngleType (90.1)).toEqual("Obtuse angle");
+    expect(getAngleType (179.9)).toEqual("Obtuse angle");
+}); 
 
 // Case 4: Identify Straight Angles:
 // When the angle is exactly 180 degrees,
 // Then the function should return "Straight angle"
-// ====> write your test here, and then add a line to pass the test in the function above
 
+test("should identify straight angle (180°)", () => {
+    expect(getAngleType(180)).toEqual("Straight angle");
+});
 // Case 5: Identify Reflex Angles:
 // When the angle is greater than 180 degrees and less than 360 degrees,
 // Then the function should return "Reflex angle"
-// ====> write your test here, and then add a line to pass the test in the function above
\ No newline at end of file
+
+test("should identify reflex angles (180.1° and 359.9°)", () => {
+    expect(getAngleType(180.1)).toEqual("Reflex angle");
+    expect(getAngleType (359.9)).toEqual("Reflex angle");
+  });
diff --git a/Sprint-3/1-key-implement/2-is-proper-fraction.js b/Sprint-3/1-key-implement/2-is-proper-fraction.js
index 91583e941..3a8597095 100644
--- a/Sprint-3/1-key-implement/2-is-proper-fraction.js
+++ b/Sprint-3/1-key-implement/2-is-proper-fraction.js
@@ -40,6 +40,7 @@ assertEquals(improperFraction, false);
 // target output: true
 // Explanation: The fraction -4/7 is a proper fraction because the absolute value of the numerator (4) is less than the denominator (7). The function should return true.
 const negativeFraction = isProperFraction(-4, 7);
+assertEquals(properFraction, true);
 // ====> complete with your assertion
 
 // Equal Numerator and Denominator check:
@@ -51,3 +52,17 @@ const equalFraction = isProperFraction(3, 3);
 
 // Stretch:
 // What other scenarios could you test for?
+// fraction is true because the absolute value of the numerator (0) is less than the denominator (5).
+assertEquals(isProperFraction (0, 5), true)
+
+// fraction is fa;se because the absolute value of the numerator (3) is greater than the denominator (0).
+assertEquals(isProperFraction(3, 0), false);
+
+// fraction is true because the absolute value of the numerator (2) is less than the denominator (-5).
+assertEquals(isProperFraction(2, -5), true);
+
+// fraction is false because the absolute value of the numerator (-3) is greater than the denominator (-4).
+assertEquals(isProperFraction(-3, -4), false);
+
+// fraction is true because the absolute value of the numerator (-9) is less than the denominator (5).
+assertEquals(isProperFraction(-9, 5), false);
\ No newline at end of file
diff --git a/Sprint-3/1-key-implement/3-get-card-value.js b/Sprint-3/1-key-implement/3-get-card-value.js
index aa1cc9f90..15af943f5 100644
--- a/Sprint-3/1-key-implement/3-get-card-value.js
+++ b/Sprint-3/1-key-implement/3-get-card-value.js
@@ -7,6 +7,7 @@
 // complete the rest of the tests and cases
 // write one test at a time, and make it pass, build your solution up methodically
 // just make one change at a time -- don't rush -- programmers are deep and careful thinkers
+// if (rank === "A") return 11;
 function getCardValue(card) {
     if (rank === "A") return 11;
 }
@@ -33,19 +34,44 @@ assertEquals(aceofSpades, 11);
 // When the function is called with such a card,
 // Then it should return the numeric value corresponding to the rank (e.g., "5" should return 5).
 const fiveofHearts = getCardValue("5♥");
+assertEquals(fiveofHearts, 5);
+const sevenofspades = getCardValue("7♠");
+assertEquals(sevenofspades , 7);
+const eightofHearts = getCardValue("8♥");
+assertEquals(eightofHearts, 8);
+const nineofdiamonds = getCardValue("9♦");
+assertEquals(nineofdiamonds, 9);
+
 // ====> write your test here, and then add a line to pass the test in the function above
 
 // Handle Face Cards (J, Q, K):
 // Given a card with a rank of "10," "J," "Q," or "K",
 // When the function is called with such a card,
 // Then it should return the value 10, as these cards are worth 10 points each in blackjack.
+const tenofSpades = getCardValue("10♠");
+assertEquals(tenofSpades("10♠"), 10);
+const jackofspades = getCardValue("J♠");
+assertEquals(jackofspades("J♠"), 10);
+const Queenofhearts = getCardValue("Q♥");
+assertEquals(Queenofhearts("Q♥"), 10);
+const Kingofhearts = getCardValue("K♥");
+assertEquals(Kingofhearts ("K♥"), 10);
+
+
 
 // Handle Ace (A):
 // Given a card with a rank of "A",
 // When the function is called with an Ace,
 // Then it should, by default, assume the Ace is worth 11 points, which is a common rule in blackjack.
+const AceCard = getCardValue("A");
+assertEquals(AceCard ("A"), 11);
 
 // Handle Invalid Cards:
 // Given a card with an invalid rank (neither a number nor a recognized face card),
 // When the function is called with such a card,
 // Then it should throw an error indicating "Invalid card rank."
+
+const invalidCards = ["Z♠", "11", "Y♠", "1♣"];
+for (const card of invalidCards) {
+  assertEquals(error.message,  "Invalid card rank");
+}
\ No newline at end of file
diff --git a/Sprint-3/2-mandatory-rewrite/1-get-angle-type.js b/Sprint-3/2-mandatory-rewrite/1-get-angle-type.js
index d61254bd7..93e872999 100644
--- a/Sprint-3/2-mandatory-rewrite/1-get-angle-type.js
+++ b/Sprint-3/2-mandatory-rewrite/1-get-angle-type.js
@@ -1,16 +1,26 @@
 function getAngleType(angle) {
-  if (angle === 90) return "Right angle";
-  // replace with your completed function from key-implement
-
+  // Ensure angle is a number and within valid bounds
+  if (typeof angle !== "number" || angle <= 0 || angle >= 360) {
+    return "Invalid angle";
+  }
+  if (angle < 90) {
+    return "Acute angle";
+  }
+  if (angle === 90) {
+    return "Right angle";
+  }
+  if (angle < 180) {
+    return "Obtuse angle";
+  }
+  if (angle === 180) {
+    return "Straight angle";
+  }
+  // Any remaining angle must be between 180 and 360 (exclusive)
+  return "Reflex angle";
 }
 
 
 
-
-
-
-
-
 // Don't get bogged down in this detail
 // Jest uses CommonJS module syntax by default as it's quite old
 // We will upgrade our approach to ES6 modules in the next course module, so for now 
diff --git a/Sprint-3/2-mandatory-rewrite/1-get-angle-type.test.js b/Sprint-3/2-mandatory-rewrite/1-get-angle-type.test.js
index b62827b7c..dfd482882 100644
--- a/Sprint-3/2-mandatory-rewrite/1-get-angle-type.test.js
+++ b/Sprint-3/2-mandatory-rewrite/1-get-angle-type.test.js
@@ -11,14 +11,32 @@ test("should identify right angle (90°)", () => {
 // When the angle is less than 90 degrees,
 // Then the function should return "Acute angle"
 
+test("should identify acute angles (e.g., 45°)", () => {
+    expect(getAngleType(45)).toEqual("Acute angle");
+    expect(getAngleType(89.9)).toEqual("Acute angle");
+}); 
+
 // Case 3: Identify Obtuse Angles:
 // When the angle is greater than 90 degrees and less than 180 degrees,
 // Then the function should return "Obtuse angle"
 
+test("should identify obtuse angles (e.g., 90.1° and 179.9°)", () => {
+    expect(getAngleType (90.1)).toEqual("Obtuse angle");
+    expect(getAngleType (179.9)).toEqual("Obtuse angle");
+}); 
+
 // Case 4: Identify Straight Angles:
 // When the angle is exactly 180 degrees,
 // Then the function should return "Straight angle"
 
+test("should identify straight angle (180°)", () => {
+    expect(getAngleType(180)).toEqual("Straight angle");
+});
 // Case 5: Identify Reflex Angles:
 // When the angle is greater than 180 degrees and less than 360 degrees,
 // Then the function should return "Reflex angle"
+
+test("should identify reflex angles (180.1° and 359.9°)", () => {
+    expect(getAngleType(180.1)).toEqual("Reflex angle");
+    expect(getAngleType (359.9)).toEqual("Reflex angle");
+});
\ No newline at end of file
diff --git a/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.js b/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.js
index 9836fe398..63c51b36f 100644
--- a/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.js
+++ b/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.js
@@ -1,6 +1,11 @@
+
 function isProperFraction(numerator, denominator) {
-    if (numerator < denominator) return true;
-    // add your completed function from key-implement here
+  // Check for invalid fraction (denominator cannot be zero)
+  if (denominator === 0) {
+    return false;
+  }
+  // Check if the absolute value of the numerator is less than the absolute value of the denominator
+  return Math.abs(numerator) < Math.abs(denominator);
 }
 
-module.exports = isProperFraction;
\ No newline at end of file
+module.exports = isProperFraction;
diff --git a/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.test.js b/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.test.js
index ff1cc8173..08d5b7781 100644
--- a/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.test.js
+++ b/Sprint-3/2-mandatory-rewrite/2-is-proper-fraction.test.js
@@ -5,7 +5,16 @@ test("should return true for a proper fraction", () => {
 });
 
 // Case 2: Identify Improper Fractions:
+test("should return false for a Improper fraction", () => {
+  expect(isProperFraction(5, 3)).toEqual(false);
+});
 
 // Case 3: Identify Negative Fractions:
+test("should return true for negative fraction", () => {
+  expect(isProperFraction(-2, 3)).toEqual(true);
+});
 
 // Case 4: Identify Equal Numerator and Denominator:
+test("should return false for equal numerator and denominator", () => {
+  expect(isProperFraction(3, 3)).toEqual(false);
+});
diff --git a/Sprint-3/2-mandatory-rewrite/3-get-card-value.js b/Sprint-3/2-mandatory-rewrite/3-get-card-value.js
index 0d95d3736..22d4c5998 100644
--- a/Sprint-3/2-mandatory-rewrite/3-get-card-value.js
+++ b/Sprint-3/2-mandatory-rewrite/3-get-card-value.js
@@ -1,5 +1,14 @@
 function getCardValue(card) {
-    // replace with your code from key-implement
-    return 11;
+    const rank = card.slice(0, -1); // strip off the suit emoji
+
+    if (rank === "A") return 11;
+    if (["K", "Q", "J", "10"].includes(rank)) return 10;
+
+   // Accept only exact digits 2 through 9
+    if (/^[2-9]$/.test(rank)) {
+        return Number(rank);
+    }
+    throw new Error("Invalid card rank");
 }
-module.exports = getCardValue;
\ No newline at end of file
+module.exports = getCardValue;
+   
\ No newline at end of file
diff --git a/Sprint-3/2-mandatory-rewrite/3-get-card-value.test.js b/Sprint-3/2-mandatory-rewrite/3-get-card-value.test.js
index 03a8e2f34..b8c060e97 100644
--- a/Sprint-3/2-mandatory-rewrite/3-get-card-value.test.js
+++ b/Sprint-3/2-mandatory-rewrite/3-get-card-value.test.js
@@ -5,7 +5,33 @@ test("should return 11 for Ace of Spades", () => {
     expect(aceofSpades).toEqual(11);
     });
 
-// Case 2: Handle Number Cards (2-10):
-// Case 3: Handle Face Cards (J, Q, K):
-// Case 4: Handle Ace (A):
-// Case 5: Handle Invalid Cards:
+    
+// Case 2: Handle Number Cards (2-10)
+test("should return the value of number cards (2-10)", () => {
+    const testCases = [
+        ["2♣", 2],
+        ["5♠", 5],
+        ["10♦", 10]
+    ];
+    testCases.forEach(([card, expected]) => {
+        expect(getCardValue(card)).toEqual(expected);
+    });
+});
+
+test("should return 10 for 10 of Diamonds", () => {
+    const ten = getCardValue("10♦");
+    expect(ten).toEqual(10);
+});
+
+// Case 3: Handle Face Cards (J, Q, K)
+test("should return 10 for face cards J, Q, K", () => {
+    expect(getCardValue("J♠")).toEqual(10);
+    expect(getCardValue("Q♣")).toEqual(10);
+    expect(getCardValue("K♥")).toEqual(10);
+});
+
+// Case 5: Handle Invalid Cards
+test("should throw error for invalid card Z♠", () => {
+    expect(() => getCardValue("Z♠")).toThrow("Invalid card rank");
+});
+
diff --git a/Sprint-3/3-mandatory-practice/implement/count.js b/Sprint-3/3-mandatory-practice/implement/count.js
index fce249650..5777801e9 100644
--- a/Sprint-3/3-mandatory-practice/implement/count.js
+++ b/Sprint-3/3-mandatory-practice/implement/count.js
@@ -1,5 +1,11 @@
 function countChar(stringOfCharacters, findCharacter) {
-    return 5
+    let count = 0;
+    for (let char of stringOfCharacters) {
+        if (char === findCharacter) {
+            count++;
+        }
+    }
+    return count;
 }
 
-module.exports = countChar;
\ No newline at end of file
+module.exports = countChar;
diff --git a/Sprint-3/3-mandatory-practice/implement/count.test.js b/Sprint-3/3-mandatory-practice/implement/count.test.js
index 42baf4b4b..12808648f 100644
--- a/Sprint-3/3-mandatory-practice/implement/count.test.js
+++ b/Sprint-3/3-mandatory-practice/implement/count.test.js
@@ -1,5 +1,5 @@
 // implement a function countChar that counts the number of times a character occurs in a string
-const countChar = require("./count");
+
 // Given a string str and a single character char to search for,
 // When the countChar function is called with these inputs,
 // Then it should:
@@ -9,6 +9,7 @@ const countChar = require("./count");
 // And a character char that may occur multiple times with overlaps within str (e.g., 'a' in 'aaaaa'),
 // When the function is called with these inputs,
 // Then it should correctly count overlapping occurrences of char (e.g., 'a' appears five times in 'aaaaa').
+const countChar = require("./count");
 
 test("should count multiple occurrences of a character", () => {
   const str = "aaaaa";
@@ -22,3 +23,10 @@ test("should count multiple occurrences of a character", () => {
 // And a character char that does not exist within the case-sensitive str,
 // When the function is called with these inputs,
 // Then it should return 0, indicating that no occurrences of the char were found in the case-sensitive str.
+
+test("should return 0 if the character does not exist in the string", () => {
+  const str = "hello";
+  const char = "z";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
\ No newline at end of file
diff --git a/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.js b/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.js
deleted file mode 100644
index 24f528b0d..000000000
--- a/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.js
+++ /dev/null
@@ -1,5 +0,0 @@
-function getOrdinalNumber(num) {
- return "1st";
-}
-
-module.exports = getOrdinalNumber;
\ No newline at end of file
diff --git a/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.test.js b/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.test.js
index 6d55dfbb4..b53341af9 100644
--- a/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.test.js
+++ b/Sprint-3/3-mandatory-practice/implement/get-ordinal-number.test.js
@@ -1,13 +1,35 @@
-const getOrdinalNumber = require("./get-ordinal-number");
 // In this week's prep, we started implementing getOrdinalNumber
 
 // continue testing and implementing getOrdinalNumber for additional cases
 // Write your tests using Jest - remember to run your tests often for continual feedback
 
-// Case 1: Identify the ordinal number for 1
-// When the number is 1,
-// Then the function should return "1st"
+const getOrdinalNumber = require("./getOrdinalNumber");
 
-test("should return '1st' for 1", () => {
-    expect(getOrdinalNumber(1)).toEqual("1st");
-    });
+test("returns 1st for 1", () => {
+  expect(getOrdinalNumber(1)).toBe("1st");
+});
+
+  test("returns 2nd for 2", () => {
+  expect(getOrdinalNumber(2)).toBe("2nd");
+});
+
+test("returns 3rd for 3", () => {
+  expect(getOrdinalNumber(3)).toBe("3rd");
+});
+
+test("returns 4th for 4", () => {
+  expect(getOrdinalNumber(4)).toBe("4th");
+});
+
+test("Handle the special case for teens (11, 12, 13)", () => {
+  expect(getOrdinalNumber(11)).toBe("11th");
+  expect(getOrdinalNumber(12)).toBe("12th");
+  expect(getOrdinalNumber(13)).toBe("13th");
+});
+
+test("Get the last digit to determine suffix", () => {
+  expect(getOrdinalNumber(21)).toBe("21st");
+  expect(getOrdinalNumber(22)).toBe("22nd");
+  expect(getOrdinalNumber(23)).toBe("23rd");
+  expect(getOrdinalNumber(101)).toBe("101st");
+});
diff --git a/Sprint-3/3-mandatory-practice/implement/getOrdinalNumber.js b/Sprint-3/3-mandatory-practice/implement/getOrdinalNumber.js
new file mode 100644
index 000000000..9ce5a7cf3
--- /dev/null
+++ b/Sprint-3/3-mandatory-practice/implement/getOrdinalNumber.js
@@ -0,0 +1,20 @@
+function getOrdinalNumber(num) {
+  const lastDigit = num % 10;
+  const lastTwoDigits = num % 100;
+
+  if (lastTwoDigits >= 11 && lastTwoDigits <= 13) {
+    return num + "th";
+  }
+
+  switch (lastDigit) {
+    case 1:
+      return num + "st";
+    case 2:
+      return num + "nd";
+    case 3:
+      return num + "rd";
+    default:
+      return num + "th";
+  }
+}
+module.exports = getOrdinalNumber;
diff --git a/Sprint-3/3-mandatory-practice/implement/repeat.js b/Sprint-3/3-mandatory-practice/implement/repeat.js
index 621f9bd35..3b7a40ffe 100644
--- a/Sprint-3/3-mandatory-practice/implement/repeat.js
+++ b/Sprint-3/3-mandatory-practice/implement/repeat.js
@@ -1,5 +1,9 @@
-function repeat() {
-    return "hellohellohello";
+function repeat(str = "", count = 1) {
+  if (count < 0) {
+    throw new Error("Invalid count");
+  }
+
+  return str.repeat(count);
 }
 
-module.exports = repeat;
\ No newline at end of file
+module.exports = repeat;
diff --git a/Sprint-3/3-mandatory-practice/implement/repeat.test.js b/Sprint-3/3-mandatory-practice/implement/repeat.test.js
index 8a4ab42ef..d2d675533 100644
--- a/Sprint-3/3-mandatory-practice/implement/repeat.test.js
+++ b/Sprint-3/3-mandatory-practice/implement/repeat.test.js
@@ -30,3 +30,34 @@ test("should repeat the string count times", () => {
 // Given a target string str and a negative integer count,
 // When the repeat function is called with these inputs,
 // Then it should throw an error or return an appropriate error message, as negative counts are not valid.
+
+// Case: Repeat string multiple times
+test("should repeat the string count times", () => {
+  const str = "hello";
+  const count = 3;
+  const repeatedStr = repeat(str, count);
+  expect(repeatedStr).toEqual("hellohellohello");
+});
+
+// Case: Handle count of 1
+test("should return the original string if count is 1", () => {
+  const str = "test";
+  const count = 1;
+  const repeatedStr = repeat(str, count);
+  expect(repeatedStr).toEqual("test");
+});
+
+// Case: Handle count of 0
+test("should return an empty string if count is 0", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeat(str, count);
+  expect(repeatedStr).toEqual("");
+});
+
+// Case: Negative count
+test("should throw an error if count is negative", () => {
+  const str = "hello";
+  const count = -2;
+  expect(() => repeat(str, count)).toThrow("Invalid count");
+});
diff --git a/Sprint-3/4-stretch-investigate/card-validator.js b/Sprint-3/4-stretch-investigate/card-validator.js
new file mode 100644
index 000000000..ee1d5ea3e
--- /dev/null
+++ b/Sprint-3/4-stretch-investigate/card-validator.js
@@ -0,0 +1,32 @@
+function validateCreditCard(cardNumber) {
+  // Check length and numeric characters
+  if (cardNumber.length !== 16 || !/^\d{16}$/.test(cardNumber)) {
+    return false;
+  }
+
+  // Check at least two different digits
+  const uniqueDigits = new Set(cardNumber);
+  if (uniqueDigits.size < 2) {
+    return false;
+  }
+
+  // Check last digit is even
+  const lastDigit = Number(cardNumber[cardNumber.length - 1]);
+  if (lastDigit % 2 !== 0) {
+    return false;
+  }
+
+  // Check sum of digits
+  let digitSum = 0;
+  for (let digit of cardNumber) {
+    digitSum += Number(digit);
+  }
+  if (digitSum <= 16) {
+    return false;
+  }
+
+  // If all checks passed, return true
+  return true;
+}
+
+module.exports = validateCreditCard;
diff --git a/Sprint-3/4-stretch-investigate/card-validator.md b/Sprint-3/4-stretch-investigate/card-validator.md
index e39c6ace6..da0aa654d 100644
--- a/Sprint-3/4-stretch-investigate/card-validator.md
+++ b/Sprint-3/4-stretch-investigate/card-validator.md
@@ -33,3 +33,6 @@ These are the requirements your project needs to fulfill:
 - Return a boolean from the function to indicate whether the credit card number is valid.
 
 Good luck!
+
+
+
diff --git a/Sprint-3/4-stretch-investigate/find.js b/Sprint-3/4-stretch-investigate/find.js
index c7e79a2f2..b34382ead 100644
--- a/Sprint-3/4-stretch-investigate/find.js
+++ b/Sprint-3/4-stretch-investigate/find.js
@@ -18,8 +18,19 @@ console.log(find("code your future", "z"));
 
 // Use the Python Visualiser to help you play computer with this example and observe how this code is executed
 // Pay particular attention to the following:
+/* a) how does the index variable update during the call to find?
+index starts at 0, and it increases by 1 on each loop iteration using index++.
+It keeps track of the current position in the string as you check each character.
 
-// a) How the index variable updates during the call to find
-// b) What is the if statement used to check
-// c) Why is index++ being used?
-// d) What is the condition index < str.length used for?
+b) What is the if statement used to check
+This checks whether the character at the current index matches the target character. 
+If it does, the function returns the index and stops running.
+
+c) Why is index++ being used?
+index++ increments the index by 1 after each check, so the loop continues moving forward through the string.
+Without this, the loop would get stuck on the same character instead of running through the rest of the string.
+
+d) What is the condition index < str.length used for?
+This ensures the loop runs only while index is within the bounds of the string.
+It prevents accessing characters beyond the end of the string.
+*/
diff --git a/Sprint-3/4-stretch-investigate/password-validator.js b/Sprint-3/4-stretch-investigate/password-validator.js
index b55d527db..9ebd413b8 100644
--- a/Sprint-3/4-stretch-investigate/password-validator.js
+++ b/Sprint-3/4-stretch-investigate/password-validator.js
@@ -1,6 +1,29 @@
+const previousPasswords = ["Password123!", "Welcome1$", "Admin#2023"]; // example previous passwords list
+
 function passwordValidator(password) {
-    return password.length < 5 ? false : true
-}
+  
+  // Check that password is a string
+  if (typeof password !== "string") return false;
+  // Check minimum length
+  if (password.length < 5) return false;
+
+  // Check for at least one uppercase letter
+  if (!/[A-Z]/.test(password)) return false;
+
+  // Check for at least one lowercase letter
+  if (!/[a-z]/.test(password)) return false;
 
+  // Check for at least one digit
+  if (!/[0-9]/.test(password)) return false;
+
+  // Check for at least one special character from allowed set
+  if (!/[!#$%.*&]/.test(password)) return false;
+
+  // Check password not previously used
+  if (previousPasswords.includes(password)) return false;
+
+  // If all checks pass, password is valid
+  return true;
+}
 
-module.exports = passwordValidator;
\ No newline at end of file
+module.exports = passwordValidator;
diff --git a/Sprint-3/4-stretch-investigate/password-validator.test.js b/Sprint-3/4-stretch-investigate/password-validator.test.js
index 8fa3089d6..7e91b3c36 100644
--- a/Sprint-3/4-stretch-investigate/password-validator.test.js
+++ b/Sprint-3/4-stretch-investigate/password-validator.test.js
@@ -14,13 +14,34 @@ To be valid, a password must:
 
 You must breakdown this problem in order to solve it. Find one test case first and get that working
 */
-const isValidPassword = require("./password-validator");
-test("password has at least 5 characters", () => {
-    // Arrange
-    const password = "12345";
-    // Act
-    const result = isValidPassword(password);
-    // Assert
-    expect(result).toEqual(true);
-}
-);
\ No newline at end of file
+ // Assert
+    
+const passwordValidator= require("./password-validator");
+
+  test("Password must be at least 5 characters long.", () => {
+    expect(passwordValidator("St1!")).toBe(false);
+});
+
+  test("password with exactly 5 valid characters long", () => {
+  expect(isValidPassword("Stg1!")).toBe(true);
+});
+  test("Password must include at least one uppercase letter.", () =>{
+    expect(passwordValidator("strong1!")).toBe(false);
+  } )
+  
+  test("Password must include at least one lowercase letter.", () =>{
+    expect(passwordValidator("STRONG1")).toBe(false);
+  } )
+  
+  test("Password must include at least one number.", () =>{
+    expect(passwordValidator("Strong*")).toBe(false);
+  } )
+
+ test("Password must include at least one special symbol (!#$%.*&).", () =>{
+    expect(passwordValidator("Strong2")).toBe(false);
+  } )  
+
+  test("This password has already been used. Please choose a new one.", () =>{
+    expect(passwordValidator("Password123!")).toBe(false);
+    
+  })