diff --git a/src/Data/Fixed/Instances.hs b/src/Data/Fixed/Instances.hs
new file mode 100644
index 000000000..03afaeb0e
--- /dev/null
+++ b/src/Data/Fixed/Instances.hs
@@ -0,0 +1,13 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Data.Fixed.Instances
+  (
+  ) where
+
+import ClassyPrelude
+import Data.Fixed
+
+import Text.Blaze (ToMarkup(..))
+
+instance HasResolution a => ToMarkup (Fixed a) where
+  toMarkup = toMarkup . showFixed True
\ No newline at end of file
diff --git a/src/Data/Sum/Instances.hs b/src/Data/Sum/Instances.hs
new file mode 100644
index 000000000..81c99f393
--- /dev/null
+++ b/src/Data/Sum/Instances.hs
@@ -0,0 +1,13 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Data.Sum.Instances
+  (
+  ) where
+
+import ClassyPrelude
+import Data.Monoid (Sum(..))
+
+import Text.Blaze (ToMarkup(..))
+
+instance ToMarkup a => ToMarkup (Sum a) where
+  toMarkup = toMarkup . getSum
\ No newline at end of file
diff --git a/src/Foundation.hs b/src/Foundation.hs
index 885a060de..15a35a2bb 100644
--- a/src/Foundation.hs
+++ b/src/Foundation.hs
@@ -218,7 +218,6 @@ maybeDisplay :: DisplayAble m => Text -> Maybe m -> Text  -> Text
 maybeDisplay _      Nothing  _     = mempty
 maybeDisplay before (Just x) after = before <> (display x) <> after
 
--- TODO: decouple from DisplayAble
 -- Messages creates type UniWorXMessage and RenderMessage UniWorX instance
 mkMessage "UniWorX" "messages/uniworx" "de"
 mkMessageVariant "UniWorX" "Campus" "messages/campus" "de"
diff --git a/src/Import/NoModel.hs b/src/Import/NoModel.hs
index 79000ecfe..9753d0e75 100644
--- a/src/Import/NoModel.hs
+++ b/src/Import/NoModel.hs
@@ -78,6 +78,8 @@ import Data.NonNull.Instances as Import ()
 import Data.Monoid.Instances  as Import ()
 import Data.Maybe.Instances  as Import ()
 import Data.CryptoID.Instances  as Import ()
+import Data.Sum.Instances     as Import ()
+import Data.Fixed.Instances   as Import ()
 import Data.Set.Instances     as Import ()
 import Data.HashMap.Strict.Instances as Import ()
 import Data.HashSet.Instances as Import ()
diff --git a/src/Utils.hs b/src/Utils.hs
index 8f5f6c901..344b8f510 100644
--- a/src/Utils.hs
+++ b/src/Utils.hs
@@ -261,16 +261,9 @@ instance DisplayAble Rational where
       rat2float :: Rational -> Double
       rat2float = fromRational
 
-instance DisplayAble a => DisplayAble (Maybe a) where
-  display Nothing  = ""
-  display (Just x) = display x
-
 instance HasResolution a => DisplayAble (Fixed a) where
   display = pack . showFixed True
 
-instance DisplayAble a => DisplayAble (Sum a) where
-  display = display . getSum
-
 {- We do not want DisplayAble for every Show-Class:
    We want to explicitly verify that the resulting text can be displayed to the User!
    For example: UTCTime values were shown without proper format rendering!
diff --git a/templates/widgets/grading-summary/grading-summary-row.hamlet b/templates/widgets/grading-summary/grading-summary-row.hamlet
index 261b98e1a..fd6c9f73f 100644
--- a/templates/widgets/grading-summary/grading-summary-row.hamlet
+++ b/templates/widgets/grading-summary/grading-summary-row.hamlet
@@ -42,13 +42,13 @@ $#
                 $# Falls Anzahl Blätter der Zeile verschieden von Anzahl gewerterer Blätter
                 \ (_{title $ getSum $ summary ^. _numMarkedPoints})
                 $# Kurze Alternative mit Hashtag-Symbol für "Anzahl"
-                $# \ (##{display $ summary ^. _numMarkedPoints})
+                $# \ (##{summary ^. _numMarkedPoints})
       $maybe _ <- hasPoints
         <td .table__td>
-          #{display (summary ^. _sumSheetsPoints)}
+          #{summary ^. _sumSheetsPoints}
           $if ((summary ^. _numSheetsPoints) /= (summary ^. _numSheets))
             $# Falls Anzahl Blätter der Zeile verschieden von Anzahl Blätter mit Punkten
             \ (_{title $ getSum $ summary ^. _numSheetsPoints})
             $# Kurze Alternative mit Hashtag-Symbol für "Anzahl"
-            $# \ (##{display $ summary ^. _numSheetsPoints})
-      <td .table__td>#{display $ summary ^. _numSheets}
+            $# \ (##{summary ^. _numSheetsPoints})
+      <td .table__td>#{summary ^. _numSheets}