diff --git a/Exercises/1-let.js b/Exercises/1-let.js
index d705443..c321cb9 100644
--- a/Exercises/1-let.js
+++ b/Exercises/1-let.js
@@ -1,5 +1,5 @@
 'use strict';
 
-let name = undefined;
+let name = 'Alexander';
 
 module.exports = { name };
diff --git a/Exercises/2-const.js b/Exercises/2-const.js
index 5512738..d424717 100644
--- a/Exercises/2-const.js
+++ b/Exercises/2-const.js
@@ -1,5 +1,5 @@
 'use strict';
 
-const year = undefined;
+const year = 1997;
 
 module.exports = { year };
diff --git a/Exercises/3-hello.js b/Exercises/3-hello.js
index a597391..19c0fc7 100644
--- a/Exercises/3-hello.js
+++ b/Exercises/3-hello.js
@@ -1,5 +1,5 @@
 'use strict';
 
-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 31bd852..bb2f505 100644
--- a/Exercises/4-range.js
+++ b/Exercises/4-range.js
@@ -1,5 +1,17 @@
 'use strict';
 
-const range = null;
+const range = (start, end) => {
+  const length = end - start;
+
+  if (length < 0) return [];
+  const arr = [];
+
+  for (let i = 0; i <= length; i++) {
+    arr[i] = start;
+    start++;
+  }
+
+  return arr;
+};
 
 module.exports = { range };
diff --git a/Exercises/5-range-odd.js b/Exercises/5-range-odd.js
index 54bb5b4..b8d9b40 100644
--- a/Exercises/5-range-odd.js
+++ b/Exercises/5-range-odd.js
@@ -1,5 +1,18 @@
 'use strict';
 
-const rangeOdd = null;
+const rangeOdd = (start, end) => {
+  const length = end - start;
+
+  if (length < 0) return [];
+  const arr = [];
+
+  for (let i = start; i <= end; i++) {
+    if (i % 2 !== 0) {
+      arr.push(i);
+    }
+  }
+
+  return arr;
+};
 
 module.exports = { rangeOdd };
diff --git a/Exercises/6-calculate.js b/Exercises/6-calculate.js
index dfecf6b..37fa911 100644
--- a/Exercises/6-calculate.js
+++ b/Exercises/6-calculate.js
@@ -1,11 +1,20 @@
 '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 = null;
+const calculate = () => {
+  const MAX_ITERATION = 9;
+  const results = [];
+
+  for (let i = 0; i <= MAX_ITERATION; i++) {
+    results.push(average(square(i), cube(i)));
+  }
+
+  return results;
+};
 
 module.exports = { square, cube, average, calculate };
diff --git a/Exercises/7-objects.js b/Exercises/7-objects.js
index 0920026..038a36e 100644
--- a/Exercises/7-objects.js
+++ b/Exercises/7-objects.js
@@ -1,5 +1,12 @@
 'use strict';
 
-const fn = null;
+const fn = () => {
+  const person = { name: 'Alex' };
+  // let secondPerson = { name: 'Boris' };
+  const secondPerson = { name: 'Boris' };
+
+  person.name = 'Jake';
+  secondPerson.name = 'Oleg';
+};
 
 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..af55841 100644
--- a/Exercises/9-array.js
+++ b/Exercises/9-array.js
@@ -1,7 +1,16 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = [
+  { name: 'Alex', phone: '+79990259845' },
+  { name: 'Boris', phone: '+79147255521' },
+  { name: 'Jake', phone: '+79263042775' },
+  { name: 'John', phone: '+79169023517' },
+];
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => {
+  for (const obj of phonebook) {
+    if (obj.name === name) return obj.phone;
+  }
+};
 
 module.exports = { phonebook, findPhoneByName };
diff --git a/Exercises/a-hash.js b/Exercises/a-hash.js
index 466c69a..a82d1b5 100644
--- a/Exercises/a-hash.js
+++ b/Exercises/a-hash.js
@@ -1,7 +1,12 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = {
+  'Alex': '+79990259845',
+  'Boris': '+79147255521',
+  'Jake': '+79263042775',
+  'John': '+79169023517',
+};
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => phonebook[name];
 
 module.exports = { phonebook, findPhoneByName };