diff --git a/01/app.js b/01/app.js
index e69de29..5fd3c93 100644
--- a/01/app.js
+++ b/01/app.js
@@ -0,0 +1,9 @@
+let users = [
+	'Jan Kowalski',
+	'Grzegorz Małolepszy',
+	'Adam Nieproszony',
+	'Katarzyna Nowak',
+	'Olga Zarzeczna',
+];
+
+console.log(users[0], users[2], users[4], users.length);
diff --git a/02/app.js b/02/app.js
index 9ad302b..960a8e5 100644
--- a/02/app.js
+++ b/02/app.js
@@ -1,7 +1,15 @@
 const randomArray = createRandomArray();
 console.log(randomArray);
 
+for (let i = 0; i <= randomArray.length - 1; i++) {
+	console.log(randomArray[i]);
+}
+
+randomArray.forEach((num) => {
+	console.log(num);
+});
 
+console.log(randomArray[randomArray.length - 1]);
 
 // nie modyfikuj kodu poniżej!
 
@@ -9,15 +17,15 @@ console.log(randomArray);
 // 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..e3f7d23 100644
--- a/03/app.js
+++ b/03/app.js
@@ -1,2 +1,8 @@
 const n = 24;
-const oddNumbers = [];
\ No newline at end of file
+const oddNumbers = [];
+
+for (let i = 1; i <= n; i += 2) {
+	oddNumbers.push(i);
+}
+
+console.log(oddNumbers);
diff --git a/04/app.js b/04/app.js
index 8285afd..2ca7258 100644
--- a/04/app.js
+++ b/04/app.js
@@ -1 +1,3 @@
-const years = [1980, 1934, 2002, 2019];
\ No newline at end of file
+const years = [1980, 1934, 2002, 2019];
+const currentYear = new Date().getFullYear();
+const howLong = years.map((year) => currentYear - year);
diff --git a/05/app.js b/05/app.js
index 1c6bb90..d5877bf 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 sum = numbers
+	.filter((num) => num % 2 === 0)
+	.reduce((prev, curr) => curr + prev);
+
+console.log(sum);