diff --git a/1-exercises/A-accessing-values/exercise1.js b/1-exercises/A-accessing-values/exercise1.js
index 67416c69..dcf5a5ce 100644
--- a/1-exercises/A-accessing-values/exercise1.js
+++ b/1-exercises/A-accessing-values/exercise1.js
@@ -8,7 +8,7 @@ let dog = {
   breed: "Dalmatian",
   name: "Spot",
   isHungry: true,
-  happiness: 6
+  happiness: 6,
 };
 
 /*
@@ -16,8 +16,8 @@ let dog = {
   Log the name and breed of this dog using dot notation.
 */
 
-let dogName; // complete the code
-let dogBreed; // complete the code
+let dogName = dog.name; // complete the code
+let dogBreed = dog.breed; // complete the code
 
 console.log(`${dogName} is a ${dogBreed}`);
 
@@ -25,4 +25,4 @@ console.log(`${dogName} is a ${dogBreed}`);
 
   Spot is a Dalmatian
 
-*/
\ No newline at end of file
+*/
diff --git a/1-exercises/A-accessing-values/exercise2.js b/1-exercises/A-accessing-values/exercise2.js
index 5b523ace..02189d2b 100644
--- a/1-exercises/A-accessing-values/exercise2.js
+++ b/1-exercises/A-accessing-values/exercise2.js
@@ -7,7 +7,7 @@
 let capitalCities = {
   UnitedKingdom: "London",
   China: "Beijing",
-  Peru: "Lima"
+  Peru: "Lima",
 };
 
 /*
@@ -17,7 +17,7 @@ let capitalCities = {
 */
 
 let myCountry = "UnitedKingdom";
-let myCapitalCity; // complete the code
+let myCapitalCity = capitalCities[myCountry]; // complete the code
 
 console.log(myCapitalCity);
 
@@ -25,4 +25,4 @@ console.log(myCapitalCity);
 
   London
 
-*/
\ No newline at end of file
+*/
diff --git a/1-exercises/A-accessing-values/exercise3.js b/1-exercises/A-accessing-values/exercise3.js
index 2e160dd5..cb66fc91 100644
--- a/1-exercises/A-accessing-values/exercise3.js
+++ b/1-exercises/A-accessing-values/exercise3.js
@@ -21,7 +21,7 @@ let basketballTeam = {
 */
 
 // write code here
-
+basketballTeam["topPlayers"].sort().forEach((x) => console.log(x));
 
 /* EXPECTED RESULT
 
@@ -29,4 +29,4 @@ let basketballTeam = {
   Michael Jordan
   Scottie Pippen
 
-*/
\ No newline at end of file
+*/
diff --git a/1-exercises/B-setting-values/exercise1.js b/1-exercises/B-setting-values/exercise1.js
index 7d0b05c5..2c149def 100644
--- a/1-exercises/B-setting-values/exercise1.js
+++ b/1-exercises/B-setting-values/exercise1.js
@@ -10,7 +10,7 @@ let capitalCities = {
   },
   China: {
     name: "Beijing",
-  }
+  },
 };
 
 /*
@@ -24,6 +24,9 @@ let capitalCities = {
 
 // write code here
 
+capitalCities.UnitedKingdom.population = 8980000;
+capitalCities.China.population = 21500000;
+capitalCities.Peru = { name: "Lima", population: 9750000 };
 console.log(capitalCities);
 
 /* EXPECTED RESULT
@@ -34,4 +37,4 @@ console.log(capitalCities);
     Peru: { name: "Lima", population: 9750000 }
   }
 
-*/
\ No newline at end of file
+*/
diff --git a/1-exercises/B-setting-values/exercise2.js b/1-exercises/B-setting-values/exercise2.js
index 59fb7c1e..c60acd50 100644
--- a/1-exercises/B-setting-values/exercise2.js
+++ b/1-exercises/B-setting-values/exercise2.js
@@ -6,7 +6,7 @@
 let student = {
   name: "Reshma Saujani",
   examScore: 65,
-  hasPassed: false
+  hasPassed: false,
 };
 
 /*
@@ -16,6 +16,10 @@ let student = {
 */
 
 // write code here
+student["attendance"] = 90;
+student["attendance"] >= 90 && student["examScore"] > 60
+  ? (student["hasPassed"] = true)
+  : (student["hasPassed"] = false);
 
 /*
   - Write an "if" statement that changes the value of hasPassed to true
@@ -38,4 +42,4 @@ console.log(student);
     attendance: 90
   }
 
-*/
\ No newline at end of file
+*/
diff --git a/1-exercises/C-undefined-properties/exercise.js b/1-exercises/C-undefined-properties/exercise.js
index 8b00f6ce..e5ff20f7 100644
--- a/1-exercises/C-undefined-properties/exercise.js
+++ b/1-exercises/C-undefined-properties/exercise.js
@@ -15,6 +15,7 @@ let car = {
 };
 
 console.log(car["colour"]);
+//there is no key name of "colour" in the variable name car.
 
 // Example 2
 function sayHelloToUser(user) {
@@ -22,17 +23,19 @@ function sayHelloToUser(user) {
 }
 
 let user = {
-  name: "Mira"
+  name: "Mira",
 };
 
 sayHelloToUser(user);
+///there is no key name of "firstName" in the variable name user.
 
 // Example 3
 let myPet = {
   animal: "Cat",
-  getName: function() {
+  getName: function () {
     "My pet's name is Fluffy";
   },
 };
 
 console.log(myPet.getName());
+//it has to insert "return" on the "My pet's name is Fluffy"
diff --git a/1-exercises/D-object-methods/exercise.js b/1-exercises/D-object-methods/exercise.js
index 0b57f2e1..6cee0e6d 100644
--- a/1-exercises/D-object-methods/exercise.js
+++ b/1-exercises/D-object-methods/exercise.js
@@ -9,7 +9,10 @@
 
 let student = {
   // write code here
-}
+  getName: (string) => {
+    console.log(`Student name:${string}`);
+  },
+};
 
 student.getName("Daniel");
 
@@ -17,4 +20,4 @@ student.getName("Daniel");
 
   Student name: Daniel
 
-*/
\ No newline at end of file
+*/
diff --git a/2-mandatory/1-recipes.js b/2-mandatory/1-recipes.js
index 6243fa9c..44e5dc63 100644
--- a/2-mandatory/1-recipes.js
+++ b/2-mandatory/1-recipes.js
@@ -22,4 +22,79 @@
   You should write and log at least 5 recipes
 */
 
-// write code here
\ No newline at end of file
+// write code here
+const recipe1 = {
+  title: "Mole1",
+  Serves: 2,
+  Ingredients: ["cinnamon1", "cumin1", "cocoa1"],
+};
+const recipe2 = {
+  title: "Mole2",
+  Serves: 2,
+  Ingredients: ["cinnamon2", "cumin2", "cocoa2"],
+};
+const recipe3 = {
+  title: "Mole3",
+  Serves: 2,
+  Ingredients: ["cinnamon3", "cumin3", "cocoa3"],
+};
+const recipe4 = {
+  title: "Mole4",
+  Serves: 2,
+  Ingredients: ["cinnamon4", "cumin4", "cocoa4"],
+};
+const recipe5 = {
+  title: "Mole5",
+  Serves: 2,
+  Ingredients: ["cinnamon5", "cumin5", "cocoa5"],
+};
+const recipeArr = [recipe1, recipe2, recipe3, recipe4, recipe5];
+for (let i = 0; i < recipeArr.length; i++) {
+  for (const property in recipeArr[i]) {
+    if (property === "title") {
+      console.log(`${recipeArr[i][property]}`);
+    } else if (property === "Serves") {
+      console.log(`${property}:${recipeArr[i][property]}`);
+    } else if (property === "Ingredients") {
+      console.log(`${property}:`);
+      Array.from(recipeArr[i][property]).forEach((x) => console.log(x));
+      console.log(`----------------------`);
+    }
+  }
+}
+// Result:
+// Mole1
+// Serves:2
+// Ingredients:
+// cinnamon1
+// cumin1
+// cocoa1
+// ----------------------
+// Mole2
+// Serves:2
+// Ingredients:
+// cinnamon2
+// cumin2
+// cocoa2
+// ----------------------
+// Mole3
+// Serves:2
+// Ingredients:
+// cinnamon3
+// cumin3
+// cocoa3
+// ----------------------
+// Mole4
+// Serves:2
+// Ingredients:
+// cinnamon4
+// cumin4
+// cocoa4
+// ----------------------
+// Mole5
+// Serves:2
+// Ingredients:
+// cinnamon5
+// cumin5
+// cocoa5
+// ----------------------
\ No newline at end of file
diff --git a/2-mandatory/2-currency-code-lookup.js b/2-mandatory/2-currency-code-lookup.js
index 5fde14f1..31fd442f 100644
--- a/2-mandatory/2-currency-code-lookup.js
+++ b/2-mandatory/2-currency-code-lookup.js
@@ -17,10 +17,19 @@ const COUNTRY_CURRENCY_CODES = [
   ["MX", "MXN"],
 ];
 
+// Object.fromEntries way:
 function createLookup(countryCurrencyCodes) {
-  // write code here
+  return Object.fromEntries(countryCurrencyCodes);
 }
 
+//---another way if like "reduce" method---:
+// function createLookup(countryCurrencyCodes) {
+//   return countryCurrencyCodes.reduce((acc, cur) => {
+//     acc[cur[0]] = cur[1];
+//     return acc;
+//   }, {});
+// }
+
 /* ======= TESTS - DO NOT MODIFY =====
 - To run the tests for this exercise, run `npm test -- --testPathPattern 2-currency-code-lookup.js`
 - To run all exercises/tests in the mandatory folder, run `npm test`
@@ -34,4 +43,4 @@ test("creates country currency code lookup", () => {
     NG: "NGN",
     MX: "MXN",
   });
-});
\ No newline at end of file
+});
diff --git a/2-mandatory/3-shopping-list.js b/2-mandatory/3-shopping-list.js
index d25cb366..717befec 100644
--- a/2-mandatory/3-shopping-list.js
+++ b/2-mandatory/3-shopping-list.js
@@ -19,7 +19,16 @@ let pantry = {
 };
 
 function createShoppingList(recipe) {
-  // write code here
+  const resultObj = {};
+  resultObj.name = recipe.name;
+  resultObj.items = [];
+  const pantryAllList = Object.values(pantry).flat();
+
+  for (let i = 0; i < recipe.ingredients.length; i++) {
+    if (!pantryAllList.includes(recipe.ingredients[i]))
+      resultObj.items.push(recipe.ingredients[i]);
+  }
+  return resultObj;
 }
 
 /* ======= TESTS - DO NOT MODIFY =====
@@ -43,11 +52,18 @@ test("createShoppingList works for pancakes recipe", () => {
 test("createShoppingList works for margherita pizza recipe", () => {
   let recipe2 = {
     name: "margherita pizza",
-    ingredients: ["flour", "salt", "yeast", "tinned tomatoes", "oregano", "mozarella"],
+    ingredients: [
+      "flour",
+      "salt",
+      "yeast",
+      "tinned tomatoes",
+      "oregano",
+      "mozarella",
+    ],
   };
 
   expect(createShoppingList(recipe2)).toEqual({
     name: "margherita pizza",
-    items: ["flour", "yeast", "mozarella"]
+    items: ["flour", "yeast", "mozarella"],
   });
-});
\ No newline at end of file
+});
diff --git a/2-mandatory/4-restaurant.js b/2-mandatory/4-restaurant.js
index d7b81eea..ad93bdf0 100644
--- a/2-mandatory/4-restaurant.js
+++ b/2-mandatory/4-restaurant.js
@@ -20,8 +20,13 @@ const MENU = {
 };
 
 let cashRegister = {
-  // write code here
-}
+  orderBurger: (balance) => {
+    return balance >= MENU.burger ? balance - MENU.burger : balance;
+  },
+  orderFalafel: (balance) => {
+    return balance >= MENU.falafel ? balance - MENU.falafel : balance;
+  },
+};
 
 /* ======= TESTS - DO NOT MODIFY =====
 - To run the tests for this exercise, run `npm test -- --testPathPattern 4-restaurant.js`
diff --git a/3-extra/1-count-words.js b/3-extra/1-count-words.js
index 9d347ae5..3574dff0 100644
--- a/3-extra/1-count-words.js
+++ b/3-extra/1-count-words.js
@@ -24,9 +24,19 @@
 */
 
 function countWords(string) {
-  const wordCount = {};
-
-  // write code here
+  let wordCount = {};
+  let arr = [];
+  if (string.length > 0) {
+    arr = string.split(" ");
+  }
+  wordCount = arr.reduce((acc, cur) => {
+    if (cur in acc) {
+      acc[cur]++;
+    } else {
+      acc[cur] = 1;
+    }
+    return acc;
+  }, {});
 
   return wordCount;
 }
@@ -46,9 +56,13 @@ test("Code works for a small string", () => {
 });
 
 test("A string with, some punctuation", () => {
-  expect(countWords("A string with, some punctuation")).toEqual(
-    { A: 1, string: 1, "with,": 1, some: 1, punctuation: 1 }
-  );
+  expect(countWords("A string with, some punctuation")).toEqual({
+    A: 1,
+    string: 1,
+    "with,": 1,
+    some: 1,
+    punctuation: 1,
+  });
 });
 
 test("Empty string", () => {
@@ -56,7 +70,11 @@ test("Empty string", () => {
 });
 
 test("Example task string", () => {
-  expect(countWords("you're braver than you believe, stronger than you seem, and smarter than you think")).toEqual({
+  expect(
+    countWords(
+      "you're braver than you believe, stronger than you seem, and smarter than you think"
+    )
+  ).toEqual({
     "you're": 1,
     and: 1,
     "believe,": 1,