diff --git a/PowerKit.Tests/CollectionExtensionsTests.cs b/PowerKit.Tests/CollectionExtensionsTests.cs
index 41154e6..210b8b9 100644
--- a/PowerKit.Tests/CollectionExtensionsTests.cs
+++ b/PowerKit.Tests/CollectionExtensionsTests.cs
@@ -7,6 +7,58 @@ namespace PowerKit.Tests;
 
 public class CollectionExtensionsTests
 {
+    [Fact]
+    public void AddRange_Test()
+    {
+        // Arrange
+        var collection = (ICollection<int>)new List<int> { 1, 2, 3 };
+
+        // Act
+        collection.AddRange([4, 5, 6]);
+
+        // Assert
+        collection.Should().Equal(1, 2, 3, 4, 5, 6);
+    }
+
+    [Fact]
+    public void AddRange_SameCollection_Test()
+    {
+        // Arrange
+        var collection = (ICollection<int>)new List<int> { 1, 2, 3 };
+
+        // Act
+        collection.AddRange(collection);
+
+        // Assert
+        collection.Should().Equal(1, 2, 3, 1, 2, 3);
+    }
+
+    [Fact]
+    public void RemoveRange_Test()
+    {
+        // Arrange
+        var collection = (ICollection<int>)new List<int> { 1, 2, 3, 4, 5 };
+
+        // Act
+        collection.RemoveRange([2, 4]);
+
+        // Assert
+        collection.Should().Equal(1, 3, 5);
+    }
+
+    [Fact]
+    public void RemoveRange_SameCollection_Test()
+    {
+        // Arrange
+        var collection = (ICollection<int>)new List<int> { 1, 2, 3, 4, 5 };
+
+        // Act
+        collection.RemoveRange(collection);
+
+        // Assert
+        collection.Should().BeEmpty();
+    }
+
     [Fact]
     public void RemoveAll_Test()
     {
diff --git a/PowerKit/Extensions/CollectionExtensions.cs b/PowerKit/Extensions/CollectionExtensions.cs
index d3455a6..aa86ab6 100644
--- a/PowerKit/Extensions/CollectionExtensions.cs
+++ b/PowerKit/Extensions/CollectionExtensions.cs
@@ -13,6 +13,24 @@ internal static class CollectionExtensions
 {
     extension<T>(ICollection<T> source)
     {
+        /// <summary>
+        /// Adds all elements from the specified sequence to the collection.
+        /// </summary>
+        public void AddRange(IEnumerable<T> items)
+        {
+            foreach (var item in items.ToArray())
+                source.Add(item);
+        }
+
+        /// <summary>
+        /// Removes all elements in the specified sequence from the collection.
+        /// </summary>
+        public void RemoveRange(IEnumerable<T> items)
+        {
+            foreach (var item in items.ToArray())
+                source.Remove(item);
+        }
+
         /// <summary>
         /// Removes all elements from the collection that match the specified predicate.
         /// </summary>