diff --git a/fibo.js b/fibo.js
new file mode 100644
index 0000000..5af7bfc
--- /dev/null
+++ b/fibo.js
@@ -0,0 +1,28 @@
+const fibonacci = function (inWhatever){
+    if (typeof inWhatever == "number"){
+        let numb1 = 0;
+        let numb2 = 1;
+        let numb3 = numb1 + numb2;
+        let seriesFibo = [];
+
+        seriesFibo.push(numb1, numb2, numb3);
+
+        while (numb3 < inWhatever){
+            numb1 = numb2;
+            numb2 = numb3;
+            numb3 = numb1 + numb2;
+
+            seriesFibo.push(numb3);
+            console.log(seriesFibo);
+            if ( seriesFibo.indexOf(inWhatever) == -1){
+                console.log("The number isn´t part of Fibonacci series")
+            } else { console.log(seriesFibo.indexOf(inWhatever)+1) };
+        }
+    } else { console.log("Not a Number, NaN") }
+}
+fibonacci(3);
+fibonacci(6);
+fibonacci(610);
+fibonacci(13500);
+fibonacci(4181);
+fibonacci("=P");