diff --git a/Exercises/1-random.js b/Exercises/1-random.js
index ef5ccaf..c695af7 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
+  if (max === undefined) {
+    max = Math.floor(min);
+    min = 0;
+  }
+  return Math.floor(Math.random() * (max - min)) + min;
 };
 
 module.exports = { random };
diff --git a/Exercises/2-key.js b/Exercises/2-key.js
index ba7e53a..3fd1d64 100644
--- a/Exercises/2-key.js
+++ b/Exercises/2-key.js
@@ -1,9 +1,19 @@
 'use strict';
 
 const generateKey = (length, possible) => {
-  // Generate string of random characters
-  // Use Math.random() and Math.floor()
-  // See documentation at MDN
+  let result = '';
+  for (let i = 0; i < length; i++) {
+    const randi = Math.floor(
+      Math.random() * possible.length
+    );
+    result += possible[randi];
+  }
+  return result;
 };
 
+const characters = 'abcdefghijklmnopqrstuvwxyz0123456789';
+const key = generateKey(16, characters);
+console.log('result:', key); // eg599gb60q926j8i
+console.log(generateKey.toString().length + ' vs 210');
+
 module.exports = { generateKey };
diff --git a/Exercises/3-ip.js b/Exercises/3-ip.js
index 1e2c406..de2d1fc 100644
--- a/Exercises/3-ip.js
+++ b/Exercises/3-ip.js
@@ -1,11 +1,12 @@
 '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 bitShift = (acc, num) => (acc << 8) + +num;
+  return ip.split('.').reduce(bitShift, 0);
 };
 
+console.log(ipToInt() === 2130706433);
+const l = ipToInt.toString().length;
+console.log(`${l} in range [60, 150]?`, l >= 60 && l <= 150);
+
 module.exports = { ipToInt };
diff --git a/Exercises/4-methods.js b/Exercises/4-methods.js
index c1038e8..5498b6a 100644
--- a/Exercises/4-methods.js
+++ b/Exercises/4-methods.js
@@ -1,21 +1,10 @@
 '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) => {
+  const functions = Object.values(iface)
+    .filter((value) => typeof value === 'function');
+  if (functions.length === 0) return;
+  return functions.map((fn) => [fn.name, fn.length]);
 };
 
 module.exports = { methods };