diff --git a/implementations/isNaN.js b/implementations/isNaN.js
new file mode 100644
index 0000000..e4d9ca9
--- /dev/null
+++ b/implementations/isNaN.js
@@ -0,0 +1,14 @@
+/**
+ * 
+  The isNaN() method checks if passed value is NaN
+
+  MDN Link: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN
+ */
+
+Number.prototype.ownIsNaN = function ownIsNaN(value) {
+    let x = Number(value);
+    return x !== x;
+}
+
+// test cases 
+// {},'',null,undefined,' ',NaN,Infinity,true,false,'Infinity',[],new Date(),new Date().toString()
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