diff --git a/easy/number_complement.py b/easy/number_complement.py
new file mode 100644
index 0000000..e57f19e
--- /dev/null
+++ b/easy/number_complement.py
@@ -0,0 +1,12 @@
+# https://leetcode.com/problems/number-complement
+class Solution:
+    def findComplement(self, num: int) -> int:
+        def bit_length(num):
+            if num == 0:
+                return 1
+            return len(bin(num)) - 2 
+        width = bit_length(num)
+        inverted = ~num
+        mask = (1 << width) - 1
+        result = inverted & mask
+        return result