Fix average when passing an array as an argument

snippets/average.md

@@ -5,9 +5,13 @@ Returns the average of an of two or more numbers/arrays.
 Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array.
 
 ```js
-const average = (...arr) => [].concat(...arr).reduce((acc, val) => acc + val, 0) / arr.length;
+const average = (...arr) => {
+  const nums = [].concat(...arr);
+  return nums.reduce((acc, val) => acc + val, 0) / nums.length;
+};
 ```
 
 ```js
 average([1, 2, 3]); // 2
+average(1, 2, 3); // 2
 ```