diff --git a/src/Calculator/Views/DateCalculator.xaml.cpp b/src/Calculator/Views/DateCalculator.xaml.cpp
index 14269260..ffbc153a 100644
--- a/src/Calculator/Views/DateCalculator.xaml.cpp
+++ b/src/Calculator/Views/DateCalculator.xaml.cpp
@@ -225,7 +225,7 @@ void DateCalculator::RaiseLiveRegionChangedAutomationEvent(_In_ bool isDateDiffM
     TextBlockAutomationPeer::FromElement(resultTextBlock)->RaiseAutomationEvent(AutomationEvents::LiveRegionChanged);
 }
 
-void CalculatorApp::DateCalculator::AddSubtractOption_Checked(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
+void DateCalculator::AddSubtractOption_Checked(_In_ Platform::Object^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs^ e)
 {
     RaiseLiveRegionChangedAutomationEvent(/* DateDiff mode */ false);
 }
diff --git a/src/Calculator/Views/DateCalculator.xaml.h b/src/Calculator/Views/DateCalculator.xaml.h
index 3d825d08..414dc6bb 100644
--- a/src/Calculator/Views/DateCalculator.xaml.h
+++ b/src/Calculator/Views/DateCalculator.xaml.h
@@ -38,7 +38,7 @@ namespace CalculatorApp
         void OnLoaded(_In_ Platform::Object^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs^ e);
         void DateCalcOption_Changed(_In_ Platform::Object^ sender, _In_ Windows::UI::Xaml::Controls::SelectionChangedEventArgs^ e);
         void AddSubtractDateGrid_Loaded(_In_ Platform::Object^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs^ e);
-        void AddSubtractOption_Checked(Platform::Object ^ sender, Windows::UI::Xaml::RoutedEventArgs ^ e);
+        void AddSubtractOption_Checked(_In_ Platform::Object^ sender, _In_ Windows::UI::Xaml::RoutedEventArgs^ e);
         void ReselectCalendarDate(_In_ Windows::UI::Xaml::Controls::CalendarDatePicker^ calendarDatePicker, Windows::Foundation::DateTime dateTime);
         void OffsetDropDownClosed(_In_ Platform::Object^ sender, _In_ Platform::Object^ e);
         void CalendarFlyoutClosed(_In_ Platform::Object^ sender, _In_ Platform::Object^ e);