diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 37c64cc..c111ec9 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 fibMinus2 = 0
+  let fibMinus1 = 1
+  let fibN = value
+  for (let i = 2; i <=value; i++){
+      fibN = fibMinus1 + fibMinus2
+      fibMinus2 = fibMinus1
+      fibMinus1 = fibN
+  }
+  return fibN
 }
\ No newline at end of file