diff --git a/Sprint-2/debug/address.js b/Sprint-2/debug/address.js
index 940a6af83..f0d22ec4f 100644
--- a/Sprint-2/debug/address.js
+++ b/Sprint-2/debug/address.js
@@ -1,9 +1,7 @@
 // Predict and explain first...
-
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
-
 const address = {
   houseNumber: 42,
   street: "Imaginary Road",
@@ -12,4 +10,10 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+// console.log(`My house number is ${address[0]}`);
+// is trying to access a property using address[0] and address is an object, not an array.
+// it will log undefined.
+// to access the houseNumber property, we should use dot notation or bracket notation with string,and either
+// way using  object.key or object["key"]
+console.log(`My house number is ${address.houseNumber}`);
+console.log(`My house number is ${address["houseNumber"]}`);
diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 8c2125977..ebe39c1a4 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -11,6 +11,12 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+// for (const value of author) {
+//   console.log(value);
+// }
+// It will log syntax Error because Objects themselves aren’t directly iterable Unlike arrays we need to converted
+// and then we can loop
+
+for (const value of Object.values(author)) {
   console.log(value);
 }
diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index 6cbdd22cd..c46604ce8 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -3,13 +3,19 @@
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
 // How can you fix it?
-
 const recipe = {
   title: "bruschetta",
   serves: 2,
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+// console.log(`${recipe.title} serves ${recipe.serves}
+//   ingredients:
+// ${recipe}`);
+// When you using  ${recipe} in a template literal javaScript tries to convert the entire object to a string
+// it will log  [object Object].
+console.log(`${recipe.title} serves ${recipe.serves}`);
+console.log("ingredients");
+recipe.ingredients.forEach((ingredient) => {
+  console.log(ingredient);
+});
diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..fcda136fa 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,5 @@
-function contains() {}
-
+function contains(obj, propertyName) {
+  return obj && typeof obj === "object" && propertyName in obj;
+}
+// console.log(contains(({ a: 1, b: 2 }, "c")));
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..c835f7460 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -16,20 +16,31 @@ as the object doesn't contains a key of 'c'
 // Given a contains function
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
+test("contains returns true for existing property", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
 
-// Given an empty object
+// Given invalid parameters like an array
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
-
+test("contains on empty object returns false", () => {
+  expect(contains([], "a")).toBe(false);
+});
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
-
+test("Given an object with an existing property should return true", () => {
+  expect(contains({ a: 1, k: 2 }, "k")).toBe(true);
+});
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
-
+test("Given an object with none-existing property should return false", () => {
+  expect(contains({ a: 1, b: 2 }, "c")).toBe(false);
+});
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("Given an object with an existing property should return true", () => {
+  expect(contains(["k", "a"], "k")).toBe(false);
+});
diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..af77024a6 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,8 @@
-function createLookup() {
-  // implementation here
+function createLookup(nestedArr) {
+  const result = {};
+  for (const [country, currency] of nestedArr) {
+    result[country] = currency;
+  }
+  return result;
 }
-
 module.exports = createLookup;
diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..761632b39 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,35 +1,26 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
-/*
-
-Create a lookup object of key value pairs from an array of code pairs
-
-Acceptance Criteria:
-
-Given
- - An array of arrays representing country code and currency code pairs
-   e.g. [['US', 'USD'], ['CA', 'CAD']]
-
-When
- - createLookup function is called with the country-currency array as an argument
-
-Then
- - It should return an object where:
- - The keys are the country codes
- - The values are the corresponding currency codes
-
-Example
-Given: [['US', 'USD'], ['CA', 'CAD']]
-
-When
-createLookup(countryCurrencyPairs) is called
-
-Then
-It should return:
- {
-   'US': 'USD',
-   'CA': 'CAD'
- }
-*/
+// Create a lookup object of key value pairs from an array of code pairs
+
+// Acceptance Criteria:
+
+// Given
+//  - An array of arrays representing country code and currency code pairs
+//    e.g. [['US', 'USD'], ['CA', 'CAD']]
+test("creates a country currency code lookup for multiple codes", () => {
+  expect(
+    createLookup([
+      ["US", "USD"],
+      ["CA", "CAD"],
+    ])
+  ).toEqual({ US: "USD", CA: "CAD" });
+});
+
+test("creates a lookup for European and Asian countries", () => {
+  expect(
+    createLookup([
+      ["FR", "EUR"],
+      ["IN", "INR"],
+    ])
+  ).toEqual({ FR: "EUR", IN: "INR" });
+});
diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..f37b97037 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -3,14 +3,22 @@ function parseQueryString(queryString) {
   if (queryString.length === 0) {
     return queryParams;
   }
+
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    const indexOfEquals = pair.indexOf("=");
+
+    if (indexOfEquals === -1) {
+      queryParams[pair] = "";
+    } else {
+      const key = pair.slice(0, indexOfEquals);
+      const value = pair.slice(indexOfEquals + 1);
+      queryParams[key] = value;
+    }
   }
 
   return queryParams;
 }
-
+console.log(parseQueryString("equation=x=y+1"));
 module.exports = parseQueryString;
diff --git a/Sprint-2/implement/querystring.test.js b/Sprint-2/implement/querystring.test.js
index 3e218b789..d2e878ed9 100644
--- a/Sprint-2/implement/querystring.test.js
+++ b/Sprint-2/implement/querystring.test.js
@@ -3,10 +3,40 @@
 // Below is one test case for an edge case the implementation doesn't handle well.
 // Fix the implementation for this test, and try to think of as many other edge cases as possible - write tests and fix those too.
 
-const parseQueryString = require("./querystring.js")
-
+const parseQueryString = require("./querystring.js");
 test("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y+1",
+  });
+});
+test("parses simple key=value pairs", () => {
+  expect(parseQueryString("name=John&age=30")).toEqual({
+    name: "John",
+    age: "30",
+  });
+});
+
+test("parses value containing '='", () => {
+  expect(parseQueryString("equation=x=y+1")).toEqual({
+    equation: "x=y+1",
+  });
+});
+
+test("handles keys with no value", () => {
+  expect(parseQueryString("flag&key=value")).toEqual({
+    flag: "",
+    key: "value",
+  });
+});
+
+test("handles multiple '=' in value", () => {
+  expect(parseQueryString("data=key=value=extra")).toEqual({
+    data: "key=value=extra",
+  });
+});
+
+test("handles keys with empty values", () => {
+  expect(parseQueryString("name=")).toEqual({
+    name: "",
   });
 });
diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..22d08dda3 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,11 @@
-function tally() {}
-
+function tally(arr) {
+  const output = {};
+  if (!Array.isArray(arr)) {
+    throw new Error("Input must be an array");
+  }
+  arr.forEach((element) => {
+    output[element] = (output[element] || 0) + 1;
+  });
+  return output;
+}
 module.exports = tally;
diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..ec2584c3c 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -19,16 +19,25 @@ const tally = require("./tally.js");
 // Given a function called tally
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
-
+test("Given a function called tally, should return an object containing the count for each unique item", () => {
+  expect(tally(["a", "a", "a"])).toEqual({ a: 3 });
+});
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
-
+test("Given an empty array [], should returns an empty object {}", () => {
+  expect(tally([])).toEqual({});
+});
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("Given an array with duplicate items, should return counts for each unique item", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("Given an invalid input like a string,Then it should throw an error", () => {
+  expect(() => tally("string")).toThrow("Input must be an array");
+});
diff --git a/Sprint-2/interpret/invert.js b/Sprint-2/interpret/invert.js
index bb353fb1f..a7e7a557e 100644
--- a/Sprint-2/interpret/invert.js
+++ b/Sprint-2/interpret/invert.js
@@ -10,20 +10,25 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
 
 // a) What is the current return value when invert is called with { a : 1 }
-
+// {"1":"a"}
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
-
+// { "1": "a", "2": "b" }
 // c) What is the target return value when invert is called with {a : 1, b: 2}
-
+// { a: 1, b: 2 }
 // c) What does Object.entries return? Why is it needed in this program?
+// returns an array of a given object's which is  own enumerable string-keyed property key-value pairs.
 
 // d) Explain why the current return value is different from the target output
-
+// The code uses invertedObj.key = value which creates a property literally named "key" instead of dynamically using the value of key
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+console.log(invert({ a: 2, b: 3 })); // ===> { '2': 'a', '3': 'b' }
+console.log(invert({ b: 1, c: 2 })); // ===> { '1': 'b', '2': 'c' }
+console.log(invert({ code: "war" })); // ===> { war: 'code'
+console.log(invert({})); // ===> {}
diff --git a/Sprint-2/stretch/count-words.js b/Sprint-2/stretch/count-words.js
index 8e85d19d7..5e936ba17 100644
--- a/Sprint-2/stretch/count-words.js
+++ b/Sprint-2/stretch/count-words.js
@@ -26,3 +26,17 @@
 
 3. Order the results to find out which word is the most common in the input
 */
+function countWords(str) {
+  const obj = {};
+  let tidyStr = str.replace(/[!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~]/g, "");
+  let arr = tidyStr.toLowerCase().split(/\s+/);
+  arr.forEach((element) => {
+    if (obj[element]) {
+      obj[element] += 1;
+    } else {
+      obj[element] = 1;
+    }
+  });
+  return obj;
+}
+// countWords("you and mE anD you me! me");
diff --git a/Sprint-2/stretch/mode.js b/Sprint-2/stretch/mode.js
index 3f7609d79..b73a52eb4 100644
--- a/Sprint-2/stretch/mode.js
+++ b/Sprint-2/stretch/mode.js
@@ -19,8 +19,11 @@ function calculateMode(list) {
 
     freqs.set(num, (freqs.get(num) || 0) + 1);
   }
+  return highestFreq(freqs);
+}
 
-  // Find the value with the highest frequency
+// Find the value with the highest frequency
+function highestFreq(freqs) {
   let maxFreq = 0;
   let mode;
   for (let [num, freq] of freqs) {
@@ -32,5 +35,4 @@ function calculateMode(list) {
 
   return maxFreq === 0 ? NaN : mode;
 }
-
 module.exports = calculateMode;
diff --git a/Sprint-2/stretch/till.js b/Sprint-2/stretch/till.js
index 6a08532e7..4cbe47135 100644
--- a/Sprint-2/stretch/till.js
+++ b/Sprint-2/stretch/till.js
@@ -8,7 +8,8 @@ function totalTill(till) {
   let total = 0;
 
   for (const [coin, quantity] of Object.entries(till)) {
-    total += coin * quantity;
+    const formatedCoin = parseInt(coin);
+    total += formatedCoin * quantity;
   }
 
   return `£${total / 100}`;
@@ -20,12 +21,43 @@ const till = {
   "50p": 4,
   "20p": 10,
 };
+
 const totalAmount = totalTill(till);
 
 // a) What is the target output when totalTill is called with the till object
+// Sum = 10 + 30 + 200 + 200 = 440p → £4.40
 
 // b) Why do we need to use Object.entries inside the for...of loop in this function?
+//  it used to  convert the object into an array of key-value pairs.
 
 // c) What does coin * quantity evaluate to inside the for...of loop?
+// Coin is a string like "1p", "5p", etc. Multiplying a string that includes non-numeric characters by a number resulting into a NaN which is not a number.
 
 // d) Write a test for this function to check it works and then fix the implementation of totalTill
+const till1 = {
+  "11p": 5,
+  "7p": 4,
+  "40p": 3,
+  "80p": 1,
+};
+
+const expected1 = "£2.83";
+const actual1 = totalTill(till1);
+console.assert(
+  actual1 === expected1,
+  `Expected ${expected1} but got ${actual1}`
+);
+
+const till2 = {
+  "21p": 9,
+  "3p": 2,
+  "9p": 9,
+  "44p": 7,
+};
+
+const expected2 = "£5.84";
+const actual2 = totalTill(till2);
+console.assert(
+  actual2 === expected2,
+  `Expected ${expected2} but got ${actual2}`
+);