diff --git a/Exercises/.prettierrc b/Exercises/.prettierrc
new file mode 100644
index 0000000..4cb85b8
--- /dev/null
+++ b/Exercises/.prettierrc
@@ -0,0 +1,7 @@
+{
+  "trailingComma": "es5",
+  "tabWidth": 2,
+  "semi": true,
+  "singleQuote": true,
+  "space-before-function-paren": ["error", "never"]
+}
diff --git a/Exercises/1-let.js b/Exercises/1-let.js
index d705443..5c867f5 100644
--- a/Exercises/1-let.js
+++ b/Exercises/1-let.js
@@ -1,5 +1,5 @@
 'use strict';
 
-let name = undefined;
+let name = 'undefined';
 
 module.exports = { name };
diff --git a/Exercises/2-const.js b/Exercises/2-const.js
index 5512738..a8391b5 100644
--- a/Exercises/2-const.js
+++ b/Exercises/2-const.js
@@ -1,5 +1,5 @@
 'use strict';
 
-const year = undefined;
+const year = 1942;
 
 module.exports = { year };
diff --git a/Exercises/3-hello.js b/Exercises/3-hello.js
index a597391..d9bde71 100644
--- a/Exercises/3-hello.js
+++ b/Exercises/3-hello.js
@@ -1,5 +1,7 @@
 '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..579872b 100644
--- a/Exercises/4-range.js
+++ b/Exercises/4-range.js
@@ -1,5 +1,12 @@
 'use strict';
 
-const range = null;
+const range = (start, end) => {
+  const result = [];
+  for (start; start <= end; start++) {
+    result.push(start);
+  }
+
+  return result;
+};
 
 module.exports = { range };
diff --git a/Exercises/5-range-odd.js b/Exercises/5-range-odd.js
index 54bb5b4..86dda0d 100644
--- a/Exercises/5-range-odd.js
+++ b/Exercises/5-range-odd.js
@@ -1,5 +1,14 @@
 'use strict';
 
-const rangeOdd = null;
+const rangeOdd = (start, end) => {
+  const result = [];
+  for (start; start <= end; start++) {
+    if (start % 2 !== 0) {
+      result.push(start);
+    }
+  }
+
+  return result;
+};
 
 module.exports = { rangeOdd };
diff --git a/Exercises/6-calculate.js b/Exercises/6-calculate.js
index dfecf6b..0b51cba 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 = null;
+const calculate = () => {
+  const result = [];
+  for (let i = 0; i <= 9; i++) {
+    result.push(average(square(i), cube(i)));
+  }
+
+  return result;
+};
 
 module.exports = { square, cube, average, calculate };
diff --git a/Exercises/7-objects.js b/Exercises/7-objects.js
index 0920026..f7c6873 100644
--- a/Exercises/7-objects.js
+++ b/Exercises/7-objects.js
@@ -1,5 +1,13 @@
 'use strict';
 
-const fn = null;
+const fn = () => {
+  const name = 'ssdf';
+  const obj1 = { name };
+  obj1.name = 'dsfdsfds';
+  let obj2 = { name };
+  obj2 = 'sgfsdgfs';
+
+  return { obj1, obj2 };
+};
 
 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..db50bd7 100644
--- a/Exercises/9-array.js
+++ b/Exercises/9-array.js
@@ -1,7 +1,14 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = [
+  { name: 'Marcus Aurelius', phone: '+380445554433' },
+  { name: 'Sgdsfgger', phone: '+6346346' },
+];
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => {
+  for (const item of phonebook) {
+    if (item.name === name) return item.phone;
+  }
+};
 
 module.exports = { phonebook, findPhoneByName };
diff --git a/Exercises/a-hash.js b/Exercises/a-hash.js
index 466c69a..773c42f 100644
--- a/Exercises/a-hash.js
+++ b/Exercises/a-hash.js
@@ -1,7 +1,10 @@
 'use strict';
 
-const phonebook = null;
+const phonebook = {
+  Marcus: '+380445554433',
+  Timur: '+380661874632',
+};
 
-const findPhoneByName = null;
+const findPhoneByName = (name) => phonebook[name];
 
 module.exports = { phonebook, findPhoneByName };