diff --git a/number-zoo-patrol/index.js b/number-zoo-patrol/index.js
new file mode 100644
index 0000000..a92dd36
--- /dev/null
+++ b/number-zoo-patrol/index.js
@@ -0,0 +1,10 @@
+// https://www.codewars.com/kata/number-zoo-patrol/train/javascript
+
+function findNumber(arr) {
+  let max = Math.max(...arr);
+  for (let i = 1; i < max; ++i) {
+    if (arr.indexOf(i) < 0) {
+      return i;
+    }
+  }
+}
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