diff --git a/01-intro/01-sum/sum.js b/01-intro/01-sum/sum.js
index c45d4c3..d7ec502 100644
--- a/01-intro/01-sum/sum.js
+++ b/01-intro/01-sum/sum.js
@@ -1,3 +1,7 @@
 export default function sum(a, b) {
-  /* ваш код */
+  if (typeof a != 'number' || typeof b != 'number') {
+    throw new TypeError("Arguments must be numbers");
+  }
+
+  return a + b;
 }