diff --git a/Exercises/1-random.js b/Exercises/1-random.js
index ef5ccaf..b14a2ff 100644
--- a/Exercises/1-random.js
+++ b/Exercises/1-random.js
@@ -1,9 +1,14 @@
 'use strict';
 
 const random = (min, max) => {
-  // Generate random Number between from min to max
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  if (max === undefined) {
+    max = min;
+    min = 0;
+  }
+  return Math.floor(Math.random() * (max - min) + min);
 };
+// Generate random Number between from min to max
+// Use Math.random() and Math.floor()
+// See documentation at MDN
 
 module.exports = { random };
diff --git a/Exercises/2-key.js b/Exercises/2-key.js
index ba7e53a..6d6f3ba 100644
--- a/Exercises/2-key.js
+++ b/Exercises/2-key.js
@@ -1,9 +1,13 @@
 'use strict';
 
 const generateKey = (length, possible) => {
-  // Generate string of random characters
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  const strLen = possible.length;
+  let arr = '';
+  for (let i = 0; i < length; i++) {
+    const item = Math.floor(Math.random() * strLen);
+    arr += possible[item];
+  }
+  return arr;
 };
 
 module.exports = { generateKey };
diff --git a/Exercises/3-ip.js b/Exercises/3-ip.js
index 5b448dd..206c406 100644
--- a/Exercises/3-ip.js
+++ b/Exercises/3-ip.js
@@ -1,11 +1,8 @@
 'use strict';
 
 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 fn = (res, item) => (res << 8) + parseInt(item);
+  return ip.split('.').reduce(fn, 0);
 };
 
 module.exports = { ipToInt };
diff --git a/Exercises/4-methods.js b/Exercises/4-methods.js
index c1038e8..d05c0d4 100644
--- a/Exercises/4-methods.js
+++ b/Exercises/4-methods.js
@@ -1,21 +1,14 @@
 'use strict';
 
 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 arr = [];
+  for (const item in iface) {
+    const fn = iface[item];
+    if (typeof fn === 'function') {
+      arr.push([item, fn.length]);
+    }
+  }
+  return arr;
 };
 
 module.exports = { methods };