diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 37c64cc..7ef7188 100644
--- a/04-fibonacci/index.js
+++ b/04-fibonacci/index.js
@@ -1,4 +1,11 @@
 export function fibonacci(value) {
-  // implementar logica aqui
-  
-}
\ No newline at end of file
+  if (value == 0) return 0;
+  let firstValue = 0;
+  let secondValue = 1;
+  for (let i = 2; i <= value; i++) {
+    let newValue = firstValue;
+    firstValue = secondValue;
+    secondValue += newValue;
+  }
+  return secondValue;
+}