diff --git a/01/app.js b/01/app.js
index e69de29..9c1e12f 100644
--- a/01/app.js
+++ b/01/app.js
@@ -0,0 +1,19 @@
+const users = [
+  "Alex Carter",
+  "Jamie Reynolds",
+  "Morgan Hayes",
+  "Taylor Benson",
+  "Riley Sutton",
+  "Casey Mitchell",
+  "Jordan Fletcher",
+  "Avery Collins",
+  "Cameron Lawson",
+  "Dakota Pierce",
+];
+console.log(`
+  1st name: ${users[0]}
+  3th name: ${users[2]}
+  5th name: ${users[4]}
+  Users array: ${users}
+  Array length: ${users.length}
+  `);
diff --git a/02/app.js b/02/app.js
index 9ad302b..6f046b3 100644
--- a/02/app.js
+++ b/02/app.js
@@ -1,23 +1,34 @@
 const randomArray = createRandomArray();
 console.log(randomArray);
 
+for (let i = 0; i < randomArray.length; i++) {
+  console.log(`Index ${i}: ${randomArray[i]}`);
+}
+
+console.log("\n");
 
+randomArray.forEach(function (num, index) {
+  console.log(`Index ${index}: ${num}`);
+});
 
+console.log("\n");
+
+console.log(`Last element: ${randomArray[randomArray.length - 1]}`);
 // nie modyfikuj kodu poniżej!
 
 // funkcję może deklarować poniżej wywołania
 // ponieważ w JS występuje mechanizm tzw. hoisting-u
 
 function createRandomArray() {
-    const arr = [];
-    const len = getRandomInteger(1, 10)
-    for(let i=0; i<len; i++) {
-        arr.push( getRandomInteger(1, 100) );
-    }
+  const arr = [];
+  const len = getRandomInteger(1, 10);
+  for (let i = 0; i < len; i++) {
+    arr.push(getRandomInteger(1, 100));
+  }
 
-    return arr;
+  return arr;
 }
 
 function getRandomInteger(min, max) {
-    return Math.round(Math.random() * (max-min) + min);
-}
\ No newline at end of file
+  return Math.round(Math.random() * (max - min) + min);
+}
diff --git a/03/app.js b/03/app.js
index cebcbc2..3c3d6cd 100644
--- a/03/app.js
+++ b/03/app.js
@@ -1,2 +1,18 @@
 const n = 24;
-const oddNumbers = [];
\ No newline at end of file
+
+getOddNumbers(n);
+getOddNumbers(0);
+getOddNumbers(1);
+getOddNumbers(100);
+
+function getOddNumbers(n) {
+  const oddNumbers = [];
+  let counter = 0;
+  while (n > counter) {
+    counter++;
+    if (counter % 2 == 1) {
+      oddNumbers.push(counter);
+    }
+  }
+  console.log(`n=${n} => ${oddNumbers}`);
+}
diff --git a/04/app.js b/04/app.js
index 8285afd..10c863c 100644
--- a/04/app.js
+++ b/04/app.js
@@ -1 +1,7 @@
-const years = [1980, 1934, 2002, 2019];
\ No newline at end of file
+const years = [1980, 1934, 2002, 2019];
+
+const yearsPasst = years.map(function (year) {
+  return new Date().getFullYear() - year;
+});
+
+console.log(yearsPasst);
diff --git a/05/app.js b/05/app.js
index 1c6bb90..99bc36d 100644
--- a/05/app.js
+++ b/05/app.js
@@ -1 +1,7 @@
-const numbers = [1, 2, 3, 4, 5, 6, 7];
\ No newline at end of file
+const numbers = [1, 2, 3, 4, 5, 6, 7];
+
+const sumOfEvenNumbers = numbers
+  .filter((num) => num % 2 == 0)
+  .reduce((acc, num) => (acc += num));
+
+console.log(sumOfEvenNumbers);