diff --git a/Exercises/1-random.js b/Exercises/1-random.js
index ef5ccaf..d3ea6be 100644
--- a/Exercises/1-random.js
+++ b/Exercises/1-random.js
@@ -1,9 +1,11 @@
 'use strict';
 
 const random = (min, max) => {
-  // Generate random Number between from min to max
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  const fraction = Math.random();
+  const randomVal =
+    Math.floor((1 - fraction) * min + fraction * max);
+
+  return randomVal;
 };
 
 module.exports = { random };
diff --git a/Exercises/2-key.js b/Exercises/2-key.js
index ba7e53a..2d4a184 100644
--- a/Exercises/2-key.js
+++ b/Exercises/2-key.js
@@ -1,9 +1,19 @@
 'use strict';
 
+// Generate string of random characters
+// Use Math.random() and Math.floor()
+// See documentation at MDN
+
 const generateKey = (length, possible) => {
-  // Generate string of random characters
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  let key = '';
+  const base = possible.length - 1;
+
+  while (key.length < length) {
+    const index = Math.floor(Math.random() * base);
+    key += possible[index];
+  }
+
+  return key;
 };
 
 module.exports = { generateKey };
diff --git a/Exercises/3-ip.js b/Exercises/3-ip.js
index 5b448dd..6ac7e25 100644
--- a/Exercises/3-ip.js
+++ b/Exercises/3-ip.js
@@ -1,11 +1,14 @@
 'use strict';
 
+// Parse ip address as string, for example '10.0.0.1'
+// to ['10', '0', '0', '1'] to [10, 0, 0, 1]
+// and convert to Number value 167772161 with sitwise shift
+// (10 << 8 << 8 << 8) + (0 << 8 << 8) + (0 << 8) + 1 === 167772161
+// Use Array.prototype.reduce of for loop
+
 const ipToInt = (ip = '127.0.0.1') => {
-  // Parse ip address as string, for example '10.0.0.1'
-  // to ['10', '0', '0', '1'] to [10, 0, 0, 1]
-  // and convert to Number value 167772161 with sitwise shift
-  // (10 << 8 << 8 << 8) + (0 << 8 << 8) + (0 << 8) + 1 === 167772161
-  // Use Array.prototype.reduce of for loop
+  const parts = ip.split('.');
+  return parts.reduce((acc, part) => (acc << 8) + parseInt(part), 0);
 };
 
 module.exports = { ipToInt };
diff --git a/Exercises/4-methods.js b/Exercises/4-methods.js
index c1038e8..7f6e814 100644
--- a/Exercises/4-methods.js
+++ b/Exercises/4-methods.js
@@ -1,21 +1,30 @@
 'use strict';
 
+// Introspect all properties of iface object and
+// extract function names and number of arguments
+// For example: {
+//   m1: x => [x],
+//   m2: function (x, y) {
+//     return [x, y];
+//   },
+//   m3(x, y, z) {
+//     return [x, y, z];
+//   }
+// will return: [
+//   ['m1', 1],
+//   ['m2', 2],
+//   ['m3', 3]
+// ]
+
 const methods = iface => {
-  // Introspect all properties of iface object and
-  // extract function names and number of arguments
-  // For example: {
-  //   m1: x => [x],
-  //   m2: function (x, y) {
-  //     return [x, y];
-  //   },
-  //   m3(x, y, z) {
-  //     return [x, y, z];
-  //   }
-  // will return: [
-  //   ['m1', 1],
-  //   ['m2', 2],
-  //   ['m3', 3]
-  // ]
+  const res = [];
+  for (const name in iface) {
+    const property = iface[name];
+    if (typeof property === 'function')
+      res.push([name, property.length]);
+  }
+
+  return res;
 };
 
 module.exports = { methods };