diff --git a/BeefLibs/corlib/src/Int64.bf b/BeefLibs/corlib/src/Int64.bf
index 7e486487..e34f59c7 100644
--- a/BeefLibs/corlib/src/Int64.bf
+++ b/BeefLibs/corlib/src/Int64.bf
@@ -2,7 +2,7 @@ using System.Globalization;
 
 namespace System
 {
-	struct Int64 : int64, IInteger, ISigned, IFormattable, IHashable, IOpComparable, IIsNaN, IOpNegatable
+	struct Int64 : int64, IInteger, ISigned, IFormattable, IHashable, IOpComparable, IIsNaN, IOpNegatable, IOpAddable, IOpSubtractable
 	{
 		public enum ParseError
 		{
diff --git a/BeefLibs/corlib/src/UInt64.bf b/BeefLibs/corlib/src/UInt64.bf
index 05586bbc..cc1904c9 100644
--- a/BeefLibs/corlib/src/UInt64.bf
+++ b/BeefLibs/corlib/src/UInt64.bf
@@ -2,7 +2,7 @@ using System.Globalization;
 
 namespace System
 {
-	struct UInt64 : uint64, IInteger, IUnsigned, IHashable, IOpComparable, IIsNaN, IFormattable
+	struct UInt64 : uint64, IInteger, IUnsigned, IHashable, IOpComparable, IIsNaN, IFormattable, IOpAddable, IOpSubtractable
 	{
 		public const uint64 MaxValue = 0xFFFFFFFFFFFFFFFFUL;
 		public const uint64 MinValue = 0;