diff --git a/src/factorial.js b/src/factorial.js
index 4f3ae70..b323006 100644
--- a/src/factorial.js
+++ b/src/factorial.js
@@ -1,5 +1,9 @@
-const factorial = (number) => {
-  // your code here
+function factorial(num) {
+  let resultado = 1;
+  for (let i = 1; i <= num; i++) {
+    resultado *= i;
+  }
+  return resultado;
 }
 
-module.exports = factorial;
\ No newline at end of file
+module.exports = factorial;
diff --git a/src/fibonacci.js b/src/fibonacci.js
index ea3270f..4f71d34 100644
--- a/src/fibonacci.js
+++ b/src/fibonacci.js
@@ -1,5 +1,5 @@
 const fibonacci = (n) => {
-  // your code here
+ 1,1,2,3
 }
 
-module.exports = fibonacci;
\ No newline at end of file
+module.exports = fibonacci;
diff --git a/src/primalidad.js b/src/primalidad.js
index 8bdb849..220a0d3 100644
--- a/src/primalidad.js
+++ b/src/primalidad.js
@@ -1,5 +1,11 @@
-const trialDivision = (number) => {
-  // your code here
+function esPrimo(num) {
+  if (num < 2) {
+    return false;
+  }
+  for (let i = 2; i <= Math.floor(Math.sqrt(num)); i++) {
+    if (num % i === 0) {
+      return false;
+    }
+  }
+  return true;
 }
-
-module.exports = trialDivision;
\ No newline at end of file