diff --git a/Chapter 13/concurrency_chapter/eventloop-async.js b/Chapter 13/concurrency_chapter/eventloop-async.js
new file mode 100644
index 0000000..19f97fe
--- /dev/null
+++ b/Chapter 13/concurrency_chapter/eventloop-async.js	
@@ -0,0 +1,7 @@
+console.log("Hi there");
+setTimeout(() => console.log("Sorry I'm late"), 1000);
+console.log(add(4,5));
+
+function add(x, y) {
+    return x + y;
+}
\ No newline at end of file
diff --git a/Chapter 13/concurrency_chapter/eventloop-sync.js b/Chapter 13/concurrency_chapter/eventloop-sync.js
new file mode 100644
index 0000000..f904d71
--- /dev/null
+++ b/Chapter 13/concurrency_chapter/eventloop-sync.js	
@@ -0,0 +1,6 @@
+console.log("Hi there");
+add(4,5);
+
+function add(x, y) {
+    return x + y;
+}
\ No newline at end of file