diff --git a/README.md b/README.md
index 9239f3ac..65bfede3 100644
--- a/README.md
+++ b/README.md
@@ -456,6 +456,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 2652. Sum Multiples                                                | [Link](https://leetcode.com/problems/sum-multiples/)                                                | [Link](./lib/easy/2652_sum_multiples.rb)                                                | [Link](./test/easy/test_2652_sum_multiples.rb)                                                |
 | 2974. Minimum Number Game                                          | [Link](https://leetcode.com/problems/minimum-number-game/)                                          | [Link](./lib/easy/2974_minimum_number_game.rb)                                          | [Link](./test/easy/test_2974_minimum_number_game.rb)                                          |
 | 3110. Score of a String                                            | [Link](https://leetcode.com/problems/score-of-a-string/)                                            | [Link](./lib/easy/3110_score_of_a_string.rb)                                            | [Link](./test/easy/test_3110_score_of_a_string.rb)                                            |
+| 3131. Find the Integer Added to Array I                            | [Link](https://leetcode.com/problems/find-the-integer-added-to-array-i/)                            | [Link](./lib/easy/3131_find_the_integer_added_to_array_i.rb)                            | [Link](./test/easy/test_3131_find_the_integer_added_to_array_i.rb)                            |
 | 3136. Valid Word                                                   | [Link](https://leetcode.com/problems/valid-word/)                                                   | [Link](./lib/easy/3136_valid_word.rb)                                                   | [Link](./test/easy/test_3136_valid_word.rb)                                                   |
 | 3151. Special Array I                                              | [Link](https://leetcode.com/problems/special-array-i/)                                              | [Link](./lib/easy/3151_special_array_i.rb)                                              | [Link](./test/easy/test_3151_special_array_i.rb)                                              |
 | 3498. Reverse Degree of a String                                   | [Link](https://leetcode.com/problems/reverse-degree-of-a-string/)                                   | [Link](./lib/easy/3498_reverse_degree_of_a_string.rb)                                   | [Link](./test/easy/test_3498_reverse_degree_of_a_string.rb)                                   |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index 962ff221..807ec091 100644
--- a/leetcode-ruby.gemspec
+++ b/leetcode-ruby.gemspec
@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '9.2.7'
+  s.version = '9.2.8'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/easy/3131_find_the_integer_added_to_array_i.rb b/lib/easy/3131_find_the_integer_added_to_array_i.rb
new file mode 100644
index 00000000..c25af03c
--- /dev/null
+++ b/lib/easy/3131_find_the_integer_added_to_array_i.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/find-the-integer-added-to-array-i/
+# @param {Integer[]} nums1
+# @param {Integer[]} nums2
+# @return {Integer}
+def added_integer(nums1, nums2)
+  sum1 = nums1.sum
+  sum2 = nums2.sum
+  diff = sum2 - sum1
+
+  diff / nums1.size
+end
diff --git a/test/easy/test_3131_find_the_integer_added_to_array_i.rb b/test/easy/test_3131_find_the_integer_added_to_array_i.rb
new file mode 100644
index 00000000..79c4579a
--- /dev/null
+++ b/test/easy/test_3131_find_the_integer_added_to_array_i.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/easy/3131_find_the_integer_added_to_array_i'
+require 'minitest/autorun'
+
+class FindTheIntegerAddedToArrayITest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      3,
+      added_integer(
+        [2, 6, 4],
+        [9, 7, 5]
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      -5,
+      added_integer(
+        [10],
+        [5]
+      )
+    )
+  end
+
+  def test_default_three
+    assert_equal(
+      0,
+      added_integer(
+        [1, 1, 1, 1],
+        [1, 1, 1, 1]
+      )
+    )
+  end
+end