diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 37c64cc..4f10945 100644
--- a/04-fibonacci/index.js
+++ b/04-fibonacci/index.js
@@ -1,4 +1,14 @@
 export function fibonacci(value) {
   // implementar logica aqui
-  
+  if (value < 1) return 0
+           if (value <= 2) return 1
+           let fib1 = 0
+           let fib2 = 1
+           let fibN = value
+           for (let i = 2; i <=value; i++){
+                fibN = fib2 + fib1
+                fib1 = fib2            
+                fib2 = fibN
+           }
+           return fibN
 }
\ No newline at end of file