diff --git a/Exercises/1-let.js b/Exercises/1-let.js
index 49c90f5..193d404 100644
--- a/Exercises/1-let.js
+++ b/Exercises/1-let.js
@@ -2,6 +2,6 @@
 
 // Define variable to store your name as a string
 
-let name = undefined;
+let name = 'Mariia';
 
 module.exports = { name };
diff --git a/Exercises/2-const.js b/Exercises/2-const.js
index 3d82a41..11eba14 100644
--- a/Exercises/2-const.js
+++ b/Exercises/2-const.js
@@ -2,6 +2,6 @@
 
 // Define constant to store your birth year as a number
 
-const year = undefined;
+const year = 2006;
 
 module.exports = { year };
diff --git a/Exercises/3-hello.js b/Exercises/3-hello.js
index 76df912..4328fdd 100644
--- a/Exercises/3-hello.js
+++ b/Exercises/3-hello.js
@@ -2,6 +2,6 @@
 
 // Prepare function to print greeting with single argument
 
-const hello = null;
+const hello = (name) => console.log(`Hello ${name}!`);
 
 module.exports = { hello };
diff --git a/Exercises/4-range.js b/Exercises/4-range.js
index 3cba2d6..6126d88 100644
--- a/Exercises/4-range.js
+++ b/Exercises/4-range.js
@@ -3,6 +3,12 @@
 // Implement function `range(start: number, end: number): array` returning
 // array with all numbers from the range [15, 30] including endpoints
 
-const range = null;
+const range = (start, end) => {
+  const result = [];
+  for (let i = start; i <= end; i++) {
+    result.push(i);
+  }
+  return result;
+};
 
 module.exports = { range };
diff --git a/Exercises/5-range-odd.js b/Exercises/5-range-odd.js
index 2eab790..ab758ea 100644
--- a/Exercises/5-range-odd.js
+++ b/Exercises/5-range-odd.js
@@ -3,6 +3,14 @@
 // Implement function `rangeOdd(start: number, end: number)` returning
 // array with all odd numbers from the range [15, 30] including endpoints
 
-const rangeOdd = null;
+const rangeOdd = (start, end) => {
+  const result = [];
+  for (let i = start; i <= end; i++) {
+    if (i % 2 !== 0) {
+      result.push(i);
+    }
+  }
+  return result;
+};
 
 module.exports = { rangeOdd };
diff --git a/Exercises/6-calculate.js b/Exercises/6-calculate.js
index a6cbf31..4899a38 100644
--- a/Exercises/6-calculate.js
+++ b/Exercises/6-calculate.js
@@ -16,12 +16,19 @@
 Call functions `square` and `cube` in loop, then pass their
 results to function `average`. Print what `average` returns. */
 
-const square = null;
+const square = (a) => a * a;
 
-const cube = null;
+const cube = (a) => a ** 3;
 
-const average = null;
+const average = (a, b) => (a + b) / 2;
 
-const calculate = null;
+const calculate = () => {
+  const result = [];
+  for (let i = 0; i < 10; i++) {
+    const averageCalculate = average(square(i), cube(i));
+    result.push(averageCalculate);
+  }
+  return result;
+};
 
 module.exports = { square, cube, average, calculate };
diff --git a/Exercises/7-objects.js b/Exercises/7-objects.js
index c892718..7c41b8b 100644
--- a/Exercises/7-objects.js
+++ b/Exercises/7-objects.js
@@ -1,12 +1,21 @@
 'use strict';
 
-/* Do following tasks inside function `fn` (see stub: `7-objects.js`)
-- Define constant object with single field `name`.
-- Define variable object with single field `name`.
-- Try to change field `name`.
-- Try to assign other object to both identifiers.
-- Explain script behaviour. */
-
-const fn = null;
+const fn = () => {
+  const mariia = { name: 'Mariia Khorunzha' };
+  let rachel = { name: 'Rachel Amber' };
+
+  mariia.name = 'Oksana';
+  rachel.name = 'Chloe';
+
+  rachel = { name: 'Max Caulfield' };
+
+};
+
+// mariia = { name: 'Marusya Churay' } TypeError: Assignment
+// to constant variable.
+
+// Висновок: Можливо змінювати значення полів і у константі, і у змінній,
+// але змінювати посилання на об'єкт в константі неможливо.
+
 
 module.exports = { fn };
diff --git a/Exercises/8-create.js b/Exercises/8-create.js
index a3d2a41..42c3e32 100644
--- a/Exercises/8-create.js
+++ b/Exercises/8-create.js
@@ -5,6 +5,6 @@
   Example: `createUser('Marcus Aurelius', 'Roma')`
   will return object `{ name: 'Marcus Aurelius', city: 'Roma' }` */
 
-const createUser = null;
+const createUser = (name, city) => ({ name, city });
 
 module.exports = { createUser };
diff --git a/Exercises/9-array.js b/Exercises/9-array.js
index 1c93d90..2eb912c 100644
--- a/Exercises/9-array.js
+++ b/Exercises/9-array.js
@@ -9,8 +9,16 @@ Object example: `{ name: 'Marcus Aurelius', phone: '+380445554433' }`.
 `findPhoneByName(name: string): string`. Returning phone from that object
 where field `name` equals argument `name`. Use `for` loop for this search. */
 
-const phonebook = null;
+const phonebook = [{ name: 'Marcus Aurelius', phone: '+380445554433' },
+  { name: 'Volodymyr Zelenskyy', phone: '+380441112233' },
+  { name: 'Lesya Ukrainka', phone: '+380443334455' },
+  { name: 'Taras Shevchenko', phone: '+380446663344' },
+  { name: 'Ivan Franko', phone: '+380441234567' }];
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => {
+  for (const i of phonebook) {
+    if (i.name === name) return i.phone;
+  }
+};
 
 module.exports = { phonebook, findPhoneByName };
diff --git a/Exercises/a-hash.js b/Exercises/a-hash.js
index da97309..81f6756 100644
--- a/Exercises/a-hash.js
+++ b/Exercises/a-hash.js
@@ -7,8 +7,14 @@ contains `phone`.
 `findPhoneByName(name: string): string`. Returning phone from hash/object.
 Use `hash[key]` to find needed phone. */
 
-const phonebook = null;
+const phonebook = {
+  'Marcus Aurelius': { phone: '+380445554433' },
+  'Volodymyr Zelenskyy': { phone: '+380441112233' },
+  'Lesya Ukrainka': { phone: '+380443334455' },
+  'Taras Shevchenko': { phone: '+380446663344' },
+  'Ivan Franko': { phone: '+380441234567' },
+};
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => phonebook[name];
 
 module.exports = { phonebook, findPhoneByName };
diff --git a/package.json b/package.json
index fb9df45..7fcb763 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "author": "Timur Shemsedinov <timur.shemsedinov@gmail.com>",
   "license": "MIT",
   "scripts": {
-    "test": "eslint ./Exercises; hpw",
+    "test": "eslint ./Exercises && hpw",
     "ci": "eslint ./Exercises && hpw"
   },
   "dependencies": {