diff --git a/include/s0009_palindrome_number.hpp b/include/s0009_palindrome_number.hpp
new file mode 100644
index 0000000..4d11182
--- /dev/null
+++ b/include/s0009_palindrome_number.hpp
@@ -0,0 +1,13 @@
+#ifndef S0009_PALINDROME_NUMBER
+#define S0009_PALINDROME_NUMBER
+
+#include <string>
+
+using namespace std;
+
+class Solution {
+ public:
+  bool isPalindrome(int x);
+};
+
+#endif
diff --git a/src/s0009_palindrome_number.cpp b/src/s0009_palindrome_number.cpp
new file mode 100644
index 0000000..63a3981
--- /dev/null
+++ b/src/s0009_palindrome_number.cpp
@@ -0,0 +1,8 @@
+#include "s0009_palindrome_number.hpp"
+
+bool Solution::isPalindrome(int x) {
+  string s = to_string(x);
+  string r = s;
+  reverse(r.begin(), r.end());
+  return s == r;
+}
diff --git a/tests/s0009_palindrome_number.cpp b/tests/s0009_palindrome_number.cpp
new file mode 100644
index 0000000..48de79b
--- /dev/null
+++ b/tests/s0009_palindrome_number.cpp
@@ -0,0 +1,24 @@
+#include "s0009_palindrome_number.hpp"
+
+#include <gtest/gtest.h>
+
+TEST(Problem9, Case1) {
+  int i{121};
+  bool o{true};
+  Solution solution;
+  EXPECT_EQ(solution.isPalindrome(i), o);
+}
+
+TEST(Problem9, Case2) {
+  int i{-121};
+  bool o{false};
+  Solution solution;
+  EXPECT_EQ(solution.isPalindrome(i), o);
+}
+
+TEST(Problem9, Case3) {
+  int i{10};
+  bool o{false};
+  Solution solution;
+  EXPECT_EQ(solution.isPalindrome(i), o);
+}