diff --git a/vs4win/Chapter04/WritingFunctions/Program.Functions.cs b/vs4win/Chapter04/WritingFunctions/Program.Functions.cs
index 8297031..8f10cc6 100644
--- a/vs4win/Chapter04/WritingFunctions/Program.Functions.cs
+++ b/vs4win/Chapter04/WritingFunctions/Program.Functions.cs
@@ -60,7 +60,9 @@
 
   static string CardinalToOrdinal(int number)
   {
-    switch (number)
+    int lastTwoDigits = number % 100;
+
+    switch (lastTwoDigits)
     {
       case 11: // special cases for 11th to 13th
       case 12:
@@ -68,6 +70,7 @@
         return $"{number}th";
       default:
         int lastDigit = number % 10;
+
         string suffix = lastDigit switch
         {
           1 => "st",
@@ -75,13 +78,14 @@
           3 => "rd",
           _ => "th"
         };
+
         return $"{number}{suffix}";
     }
   }
 
   static void RunCardinalToOrdinal()
   {
-    for (int number = 1; number <= 40; number++)
+    for (int number = 1; number <= 1030; number++)
     {
       Write($"{CardinalToOrdinal(number)} ");
     }
diff --git a/vs4win/Chapter04/WritingFunctions/Program.cs b/vs4win/Chapter04/WritingFunctions/Program.cs
index f2a87e5..aad506b 100644
--- a/vs4win/Chapter04/WritingFunctions/Program.cs
+++ b/vs4win/Chapter04/WritingFunctions/Program.cs
@@ -11,10 +11,10 @@ decimal taxToPay = CalculateTax(amount: 149, twoLetterRegionCode: "FR");
 WriteLine($"You must pay {taxToPay} in tax.");
 */
 
-//RunCardinalToOrdinal();
+RunCardinalToOrdinal();
 
 //RunFactorial();
 
 //RunFibImperative();
 
-RunFibFunctional();
\ No newline at end of file
+//RunFibFunctional();
\ No newline at end of file
diff --git a/vscode/Chapter04/WritingFunctions/Program.Functions.cs b/vscode/Chapter04/WritingFunctions/Program.Functions.cs
index 8297031..8f10cc6 100644
--- a/vscode/Chapter04/WritingFunctions/Program.Functions.cs
+++ b/vscode/Chapter04/WritingFunctions/Program.Functions.cs
@@ -60,7 +60,9 @@
 
   static string CardinalToOrdinal(int number)
   {
-    switch (number)
+    int lastTwoDigits = number % 100;
+
+    switch (lastTwoDigits)
     {
       case 11: // special cases for 11th to 13th
       case 12:
@@ -68,6 +70,7 @@
         return $"{number}th";
       default:
         int lastDigit = number % 10;
+
         string suffix = lastDigit switch
         {
           1 => "st",
@@ -75,13 +78,14 @@
           3 => "rd",
           _ => "th"
         };
+
         return $"{number}{suffix}";
     }
   }
 
   static void RunCardinalToOrdinal()
   {
-    for (int number = 1; number <= 40; number++)
+    for (int number = 1; number <= 1030; number++)
     {
       Write($"{CardinalToOrdinal(number)} ");
     }
diff --git a/vscode/Chapter04/WritingFunctions/Program.cs b/vscode/Chapter04/WritingFunctions/Program.cs
index f2a87e5..aad506b 100644
--- a/vscode/Chapter04/WritingFunctions/Program.cs
+++ b/vscode/Chapter04/WritingFunctions/Program.cs
@@ -11,10 +11,10 @@ decimal taxToPay = CalculateTax(amount: 149, twoLetterRegionCode: "FR");
 WriteLine($"You must pay {taxToPay} in tax.");
 */
 
-//RunCardinalToOrdinal();
+RunCardinalToOrdinal();
 
 //RunFactorial();
 
 //RunFibImperative();
 
-RunFibFunctional();
\ No newline at end of file
+//RunFibFunctional();
\ No newline at end of file