diff --git a/arrays/README.md b/arrays/README.md
index 0690816e..913d9d19 100644
--- a/arrays/README.md
+++ b/arrays/README.md
@@ -9,4 +9,12 @@ Here is a simple array:
 ```javascript
 // 1, 1, 2, 3, 5, and 8 are the elements in this array
 var numbers = [1, 1, 2, 3, 5, 8];
+
+numbers.length //returns 6
+
+//add new element to the numbers 
+numbers.push(9) //returns [1, 1, 2, 3, 5, 8, 9]
+
+//remove last element
+numbers.pop() // returns [1, 1, 2, 3, 5, 8]
 ```
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diff --git a/objects/immutable.md b/objects/immutable.md
new file mode 100644
index 00000000..c0d60032
--- /dev/null
+++ b/objects/immutable.md
@@ -0,0 +1,15 @@
+# Immutable
+Immutable object values cannot be changed once it's declared.
+```js
+const obj = {
+  prop: 42
+};
+
+Object.freeze(obj); // this will freeze the values
+
+obj.prop = 33;
+// Throws an error in strict mode
+
+console.log(obj.prop);
+// expected output: 42
+```
\ No newline at end of file