diff --git a/src/2021-11/package.json b/src/2021-11/package.json
new file mode 100644
index 0000000..1ab2594
--- /dev/null
+++ b/src/2021-11/package.json
@@ -0,0 +1,15 @@
+{
+  "name": "2021-11",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "jest"
+  },
+  "keywords": [],
+  "author": "afeiship",
+  "license": "ISC",
+  "devDependencies": {
+    "jest": "^27.3.1"
+  }
+}
diff --git a/src/2021-11/sum.js b/src/2021-11/sum.js
new file mode 100644
index 0000000..41c4bff
--- /dev/null
+++ b/src/2021-11/sum.js
@@ -0,0 +1,5 @@
+function sum(a, b) {
+    return a + b;
+}
+
+module.exports = sum;
\ No newline at end of file
diff --git a/src/2021-11/sum.test.js b/src/2021-11/sum.test.js
new file mode 100644
index 0000000..61806e8
--- /dev/null
+++ b/src/2021-11/sum.test.js
@@ -0,0 +1,5 @@
+const sum = require('./sum');
+
+test('adds 1 + 2 to equal 3', () => {
+    expect(sum(1, 2)).toBe(3);
+});
\ No newline at end of file