diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 37c64cc..838b39e 100644
--- a/04-fibonacci/index.js
+++ b/04-fibonacci/index.js
@@ -1,4 +1,17 @@
 export function fibonacci(value) {
   // implementar logica aqui
-  
+  if(value < 1) return 0;
+  if(value <= 2) return 1;
+
+  let valorFib1 = 1;
+  let valorFib2 = 0;
+  let valorFibonacci = value;
+
+  for(let i = 2; i <= value; i++) {
+    valorFibonacci = valorFib1 + valorFib2;
+    valorFib2 = valorFib1;
+    valorFib1 = valorFibonacci;
+  }
+
+  return valorFibonacci;
 }
\ No newline at end of file