diff --git a/04week/loop.js b/04week/loop.js
index e69de29bb..bea853337 100644
--- a/04week/loop.js
+++ b/04week/loop.js
@@ -0,0 +1,58 @@
+// for loop
+const cars = ["ford", "chevrolet", "dodge", "mazda", "fiat"];
+for (let i = 0; i < cars.length; i++) {
+  console.log(cars[i])
+}
+// for...in loop
+const persons = {
+    firstName: "Jane",
+    lastName: "Doe",
+    birthDate: "Jan 5, 1925",
+    gender: "female",
+}
+
+// Use a for...in loop to console.log each key.
+
+var text = "";
+var x = Object.keys(persons);
+for (x in persons) {
+  text += x + " ";
+}
+console.log(text);
+
+// Use a for...in loop and if state to console.log the value associated with the key birthDate.
+
+var text1 = "";
+var x = Object.keys(persons);
+for (x in persons) {
+	if (x === 'birthDate') {
+		text1 += persons[x];
+    } 
+} 
+console.log(text1);
+
+// while loop
+let number = 0;
+while (number < 1000){
+  number ++;
+  console.log(number);
+}
+
+//do while
+let digit = 0;
+do {
+  digit += 1;
+  console.log(digit);
+} while (digit < 1000);
+
+// When is a for loop better than a while loop?
+    // A for loop runs "n" times but a while loop runs until a certain condition becomes false. If the initial condition is false, the while loop wont run at all. So if your condition is initially false, a for loop is better.
+
+// What is the difference between a for loop and a for...in loop?
+    // A for loop repeats until a specified condition evaluates to false.
+    //The for...in statement iterates a specified variable over all the enumerable properties of an object. For each distinct property, JavaScript executes the specified statements.
+
+// What is the difference between a while loop and a do...while loop?
+    // The do...while statement repeats until a specified condition evaluates to false. A while statement executes its statements as long as a specified condition evaluates to true. 
+
+    
\ No newline at end of file