diff --git a/problems/find-missing-numbder.json b/problems/find-missing-numbder.json
new file mode 100644
index 0000000..0813175
--- /dev/null
+++ b/problems/find-missing-numbder.json
@@ -0,0 +1,6 @@
+[
+  { "input": [[3, 0, 1], 3], "expected": 2 },
+  { "input": [[0, 1], 2], "expected": 2 },
+  { "input": [[9,6,4,2,3,5,7,0,1], 9], "expected": 8 },
+  { "input": [[1], 1], "expected": 0 }
+]