diff --git a/X10D/src/ByteExtensions/ByteExtensions.cs b/X10D/src/ByteExtensions/ByteExtensions.cs
index 3556a2e..507f418 100644
--- a/X10D/src/ByteExtensions/ByteExtensions.cs
+++ b/X10D/src/ByteExtensions/ByteExtensions.cs
@@ -50,7 +50,7 @@
         /// </returns>
         public static bool IsPrime(this byte value)
         {
-            return ((int)value).IsPrime();
+            return ((short)value).IsPrime();
         }
 
         /// <summary>
diff --git a/X10D/src/ByteExtensions/SByteExtensions.cs b/X10D/src/ByteExtensions/SByteExtensions.cs
index 314dcfd..b7d242f 100644
--- a/X10D/src/ByteExtensions/SByteExtensions.cs
+++ b/X10D/src/ByteExtensions/SByteExtensions.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 
 namespace X10D
 {
@@ -43,41 +43,7 @@ namespace X10D
         /// </returns>
         public static bool IsPrime(this sbyte value)
         {
-            return value switch
-            {
-                2 => true,
-                3 => true,
-                5 => true,
-                7 => true,
-                11 => true,
-                13 => true,
-                17 => true,
-                19 => true,
-                23 => true,
-                29 => true,
-                31 => true,
-                37 => true,
-                41 => true,
-                43 => true,
-                47 => true,
-                53 => true,
-                59 => true,
-                61 => true,
-                67 => true,
-                71 => true,
-                73 => true,
-                79 => true,
-                83 => true,
-                89 => true,
-                97 => true,
-                101 => true,
-                103 => true,
-                107 => true,
-                109 => true,
-                113 => true,
-                127 => true,
-                _ => false
-            };
+            return ((short)value).IsPrime();
         }
 
         /// <summary>