diff --git a/01/app.js b/01/app.js
index e69de29..c3ce0db 100644
--- a/01/app.js
+++ b/01/app.js
@@ -0,0 +1,6 @@
+function showCurrentTime() {
+  const time = new Date().toLocaleTimeString();
+  console.log(time);
+}
+
+showCurrentTime();
diff --git a/02/app.js b/02/app.js
index e69de29..bac3370 100644
--- a/02/app.js
+++ b/02/app.js
@@ -0,0 +1,4 @@
+function sayHello(firstName) {
+  console.log(`Cześć ${firstName}!`);
+}
+sayHello("Natalia");
diff --git a/03/app.js b/03/app.js
index e69de29..2f0a1b3 100644
--- a/03/app.js
+++ b/03/app.js
@@ -0,0 +1,9 @@
+const sumNumbers = function (maxNumber) {
+  let sum = 0;
+  for (let i = 1; i <= maxNumber; i++) {
+    sum = sum + i;
+  }
+  return sum;
+};
+
+console.log(sumNumbers(5));
diff --git a/04/app.js b/04/app.js
index e69de29..fbd88ff 100644
--- a/04/app.js
+++ b/04/app.js
@@ -0,0 +1,12 @@
+const runTimer = function () {
+  let counter = 0;
+  let timerId = setInterval(function () {
+    const time = new Date().toLocaleTimeString();
+    console.log(time);
+    counter++;
+    if (counter >= 5) {
+      clearInterval(timerId);
+    }
+  }, 5000);
+};
+runTimer();