diff --git a/01/app.js b/01/app.js
index e69de29..1fc15b8 100644
--- a/01/app.js
+++ b/01/app.js
@@ -0,0 +1,6 @@
+function showTime() {
+    const time = (new Date()).toLocaleTimeString();
+    console.log(time);
+}
+
+showTime();
\ No newline at end of file
diff --git a/02/app.js b/02/app.js
index e69de29..b1be5c8 100644
--- a/02/app.js
+++ b/02/app.js
@@ -0,0 +1,5 @@
+function sayHello(name) {
+    console.log("Cześć " + name + "!");
+}
+
+sayHello('Piotr');
\ No newline at end of file
diff --git a/03/app.js b/03/app.js
index e69de29..ab53dca 100644
--- a/03/app.js
+++ b/03/app.js
@@ -0,0 +1,9 @@
+const sumTo = function(limit) {
+    let sum = 0;
+    for (let i = 1; i <= limit; i++) {
+        sum = sum+i;
+    }
+    return sum; 
+};
+
+console.log(sumTo(5));
\ No newline at end of file
diff --git a/04/app.js b/04/app.js
index e69de29..47e041a 100644
--- a/04/app.js
+++ b/04/app.js
@@ -0,0 +1,15 @@
+function runTimer() {
+    let count = 0;  
+    const intervalId = setInterval(function() {
+        const time = new Date().toLocaleTimeString();
+        console.log(time); 
+        
+        count++; 
+
+        if (count === 5) {
+            clearInterval(intervalId); 
+        }
+    }, 5000); 
+}
+
+runTimer();
\ No newline at end of file