diff --git a/Exercises/1-random.js b/Exercises/1-random.js
index ef5ccaf..dda8c0b 100644
--- a/Exercises/1-random.js
+++ b/Exercises/1-random.js
@@ -1,9 +1,9 @@
 '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 random = (max, min = 0) => {
+  min = min < 0 ? 0 : min;
+  const random = Math.random() * (max - min) + min;
+  return Math.floor(random);
 };
 
 module.exports = { random };
diff --git a/Exercises/2-key.js b/Exercises/2-key.js
index ba7e53a..f690d9e 100644
--- a/Exercises/2-key.js
+++ b/Exercises/2-key.js
@@ -1,9 +1,16 @@
 'use strict';
 
+
 const generateKey = (length, possible) => {
-  // Generate string of random characters
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  let res = '';
+  const randomIdx = n => Math.floor(Math.random() * n);
+
+  for (let i = 0; i < length; i += 1) {
+    res += possible[randomIdx(possible.length)];
+  }
+
+  return res;
 };
 
+
 module.exports = { generateKey };
diff --git a/Exercises/3-ip.js b/Exercises/3-ip.js
index 1e2c406..ac65961 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 bitwise 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') => ip
+  .split('.')
+  .reverse()
+  .reduce((acc, n, i) => acc + (n << (8 * i++)), 0);
 
 module.exports = { ipToInt };
diff --git a/Exercises/4-methods.js b/Exercises/4-methods.js
index c1038e8..c229811 100644
--- a/Exercises/4-methods.js
+++ b/Exercises/4-methods.js
@@ -1,21 +1,12 @@
 '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 methods = iface => Object
+  .keys(iface)
+  .reduce((acc, key) => {
+    if (typeof iface[key] === 'function') {
+      acc.push([iface[key].name, iface[key].length]);
+    }
+    return acc;
+  }, []);
 
 module.exports = { methods };