diff --git a/01/app.js b/01/app.js
index e69de29..41ba21d 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..a7e3b53 100644
--- a/02/app.js
+++ b/02/app.js
@@ -0,0 +1,5 @@
+function sayHello(name) {
+  console.log("Cześć " + name + "!")
+}
+
+sayHello("devmentor.pl")
\ No newline at end of file
diff --git a/03/app.js b/03/app.js
index e69de29..fc810a1 100644
--- a/03/app.js
+++ b/03/app.js
@@ -0,0 +1,9 @@
+const givenAmountOfNumbers = (x) => {
+  let sum = 0
+  for (let i = 0; i <= x; i++) {
+    sum += i
+  }
+  return sum
+}
+
+console.log(sumGivenAmontOfNumbers(4))
\ No newline at end of file
diff --git a/04/app.js b/04/app.js
index e69de29..f3c80a0 100644
--- a/04/app.js
+++ b/04/app.js
@@ -0,0 +1,13 @@
+let counter = 1
+let idInterval
+const runTimer = () => {
+  const time = (new Date()).toLocaleTimeString();
+  console.log(time);
+  counter++
+
+  if (counter > 5) {
+    clearInterval(idInterval)
+  }
+}
+
+idInterval = setInterval(runTimer, 5000)
\ No newline at end of file