diff --git a/Exercises/1-let.js b/Exercises/1-let.js
index d705443..7c72d28 100644
--- a/Exercises/1-let.js
+++ b/Exercises/1-let.js
@@ -1,5 +1,5 @@
 'use strict';
 
-let name = undefined;
+let name = 'Roman';
 
 module.exports = { name };
diff --git a/Exercises/2-const.js b/Exercises/2-const.js
index 5512738..1dedd16 100644
--- a/Exercises/2-const.js
+++ b/Exercises/2-const.js
@@ -1,5 +1,5 @@
 'use strict';
 
-const year = undefined;
+const year = 1984;
 
 module.exports = { year };
diff --git a/Exercises/3-hello.js b/Exercises/3-hello.js
index a597391..9a6e380 100644
--- a/Exercises/3-hello.js
+++ b/Exercises/3-hello.js
@@ -1,5 +1,6 @@
 'use strict';
 
-const hello = null;
+const hello = name => console.log(`Hello ${name}!`);
+// hello('Roman');
 
 module.exports = { hello };
diff --git a/Exercises/4-range.js b/Exercises/4-range.js
index 31bd852..727a113 100644
--- a/Exercises/4-range.js
+++ b/Exercises/4-range.js
@@ -1,5 +1,11 @@
 'use strict';
 
-const range = null;
+const range = (start, end) => {
+  const array = [];
+  for (let i = start; i <= end; i++) {
+    array.push(i);
+  }
+  return array;
+};
 
 module.exports = { range };
diff --git a/Exercises/5-range-odd.js b/Exercises/5-range-odd.js
index 54bb5b4..2e3e1ac 100644
--- a/Exercises/5-range-odd.js
+++ b/Exercises/5-range-odd.js
@@ -1,5 +1,11 @@
 'use strict';
 
-const rangeOdd = null;
+const rangeOdd = (start, end) => {
+  const array = [];
+  for (let i = start; i <= end; i++) {
+    (i % 2 !== 0) ? array.push(i) : '';
+  }
+  return array;
+};
 
 module.exports = { rangeOdd };
diff --git a/Exercises/6-calculate.js b/Exercises/6-calculate.js
index dfecf6b..da361ef 100644
--- a/Exercises/6-calculate.js
+++ b/Exercises/6-calculate.js
@@ -1,11 +1,18 @@
 'use strict';
 
-const square = null;
+const square = x => x * x;
 
-const cube = null;
+const cube = x => x ** 3;
 
-const average = null;
+const average = (a, b) => (a + b) / 2;
+
+const calculate = (start = 0, end = 9) => {
+  const array = [];
+  for (let i = start; i <= end; i++) {
+    array.push(average(square(i), cube(i)));
+  }
+  return array;
+};
 
-const calculate = null;
 
 module.exports = { square, cube, average, calculate };
diff --git a/Exercises/7-objects.js b/Exercises/7-objects.js
index 0920026..d081fce 100644
--- a/Exercises/7-objects.js
+++ b/Exercises/7-objects.js
@@ -1,5 +1,11 @@
 'use strict';
 
-const fn = null;
+const fn = () => {
+  const object1 = { name: 'Roman' };
+  let object2 = { name: 'Serge' };
+  object1.name = 'Foma';
+  object2.name = 'Alex';
+  object2 = { url: 'https://github.com' };
+};
 
 module.exports = { fn };
diff --git a/Exercises/8-create.js b/Exercises/8-create.js
index ac27ddd..f400582 100644
--- a/Exercises/8-create.js
+++ b/Exercises/8-create.js
@@ -1,5 +1,5 @@
 'use strict';
 
-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 466c69a..2799112 100644
--- a/Exercises/9-array.js
+++ b/Exercises/9-array.js
@@ -1,7 +1,13 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = [
+  { name: 'Marcus Aurelius', phone: '+38044555443' },
+  { name: 'Alex', phone: '+91454329566' },
+];
 
-const findPhoneByName = null;
+const findPhoneByName = name => {
+  for (const person of phonebook)
+    return person.name === name ? person.phone : null;
+};
 
 module.exports = { phonebook, findPhoneByName };
diff --git a/Exercises/a-hash.js b/Exercises/a-hash.js
index 466c69a..8d0fc46 100644
--- a/Exercises/a-hash.js
+++ b/Exercises/a-hash.js
@@ -1,7 +1,10 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = {
+  marcus: { name: 'Marcus Aurelius', phone: '+380445554433' },
+  alex: { name: 'Alex Dobrov', phone: '+914543295661' }
+};
 
-const findPhoneByName = null;
+const findPhoneByName = name => phonebook[name].phone;
 
 module.exports = { phonebook, findPhoneByName };