diff --git a/exercises/atbash-cipher/AtbashCipher.cs b/exercises/atbash-cipher/AtbashCipher.cs
index db96e2df12..827d56037a 100644
--- a/exercises/atbash-cipher/AtbashCipher.cs
+++ b/exercises/atbash-cipher/AtbashCipher.cs
@@ -1,6 +1,6 @@
 using System;
 
-public class Atbash
+public static class Atbash
 {
     public static string Encode(string value)
     {
diff --git a/exercises/atbash-cipher/Example.cs b/exercises/atbash-cipher/Example.cs
index a918218e63..6885c8e753 100644
--- a/exercises/atbash-cipher/Example.cs
+++ b/exercises/atbash-cipher/Example.cs
@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using System.Linq;
 
-public class Atbash
+public static class Atbash
 {
     private const string PLAIN = "abcdefghijklmnopqrstuvwxyz";
     private const string CIPHER = "zyxwvutsrqponmlkjihgfedcba";
diff --git a/exercises/grains/Example.cs b/exercises/grains/Example.cs
index 65de26bfcd..4b152c4eed 100644
--- a/exercises/grains/Example.cs
+++ b/exercises/grains/Example.cs
@@ -1,4 +1,4 @@
-public class Grains
+public static class Grains
 {
     public static ulong Square(int n)
     {
diff --git a/exercises/grains/Grains.cs b/exercises/grains/Grains.cs
index b75b9a5057..54162d0958 100644
--- a/exercises/grains/Grains.cs
+++ b/exercises/grains/Grains.cs
@@ -1,6 +1,6 @@
 using System;
 
-public class Grains
+public static class Grains
 {
     public static ulong Square(int n)
     {
diff --git a/exercises/triangle/Example.cs b/exercises/triangle/Example.cs
index f8416c2cdb..78215581c4 100644
--- a/exercises/triangle/Example.cs
+++ b/exercises/triangle/Example.cs
@@ -8,7 +8,7 @@ public enum TriangleKind
     Scalene
 }
 
-public class Triangle
+public static class Triangle
 {
     public static TriangleKind Kind(decimal side1, decimal side2, decimal side3)
     {
diff --git a/exercises/triangle/Triangle.cs b/exercises/triangle/Triangle.cs
index c97bc92775..69a7577a1a 100644
--- a/exercises/triangle/Triangle.cs
+++ b/exercises/triangle/Triangle.cs
@@ -7,7 +7,7 @@ public enum TriangleKind
     Scalene
 }
 
-public class Triangle
+public static class Triangle
 {
     public static TriangleKind Kind(decimal side1, decimal side2, decimal side3)
     {
diff --git a/exercises/word-count/Example.cs b/exercises/word-count/Example.cs
index 91f1295b01..30a37bf919 100644
--- a/exercises/word-count/Example.cs
+++ b/exercises/word-count/Example.cs
@@ -2,7 +2,7 @@
 using System.Text.RegularExpressions;
 using System.Collections.Generic;
 
-public class Phrase
+public static class Phrase
 {
     public static IDictionary<string, int> WordCount(string phrase)
     {
diff --git a/exercises/word-count/WordCount.cs b/exercises/word-count/WordCount.cs
index 651e69f86e..42214c7db0 100644
--- a/exercises/word-count/WordCount.cs
+++ b/exercises/word-count/WordCount.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
 
-public class Phrase
+public static class Phrase
 {
     public static IDictionary<string, int> WordCount(string phrase)
     {
diff --git a/exercises/wordy/Example.cs b/exercises/wordy/Example.cs
index 36865936c4..c6b4a0d4d5 100644
--- a/exercises/wordy/Example.cs
+++ b/exercises/wordy/Example.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 
-public class WordProblem
+public static class WordProblem
 {
     private static readonly Regex VariableAndOperatorGroupsRegex =
         new Regex(string.Format(@"{0} {1} {0}\s*{1}*\s*{0}*", @"(-?\d+)", "(plus|minus|multiplied by|divided by)"));
diff --git a/exercises/wordy/Wordy.cs b/exercises/wordy/Wordy.cs
index d33388e8d5..cdb4c52037 100644
--- a/exercises/wordy/Wordy.cs
+++ b/exercises/wordy/Wordy.cs
@@ -1,6 +1,6 @@
 using System;
 
-public class WordProblem
+public static class WordProblem
 {
     public static int Solve(string problem)
     {