diff --git a/code/Angabe4.lhs b/code/Angabe4.lhs
index a61611b..8af8dff 100644
--- a/code/Angabe4.lhs
+++ b/code/Angabe4.lhs
@@ -45,53 +45,6 @@ Datenstrukturen fuer eine einfache Buchhaltung:
 
 Helper functions:
 
-> day_to_str :: Tag -> String
-> day_to_str I = "01"
-> day_to_str II = "02"
-> day_to_str III = "03"
-> day_to_str IV = "04"
-> day_to_str V = "05"
-> day_to_str VI = "06"
-> day_to_str VII = "07"
-> day_to_str VIII = "08"
-> day_to_str IX = "09"
-> day_to_str X = "10"
-> day_to_str XI = "11"
-> day_to_str XII = "12"
-> day_to_str XIII = "13"
-> day_to_str XIV = "14"
-> day_to_str XV = "15"
-> day_to_str XVI = "16"
-> day_to_str XVII = "17"
-> day_to_str XVIII = "18"
-> day_to_str XIX = "19"
-> day_to_str XX = "20"
-> day_to_str XXI = "21"
-> day_to_str XXII = "22"
-> day_to_str XXIII = "23"
-> day_to_str XXIV = "24"
-> day_to_str XXV = "25"
-> day_to_str XXVI = "26"
-> day_to_str XXVII = "27"
-> day_to_str XXVIII = "28"
-> day_to_str XXIX = "29"
-> day_to_str XXX = "30"
-> day_to_str XXXI = "31"
-
-> month_to_str :: Monat -> String
-> month_to_str Jan = "01"
-> month_to_str Feb = "02"
-> month_to_str Mar = "03"
-> month_to_str Apr = "04"
-> month_to_str Mai = "05"
-> month_to_str Jun = "06"
-> month_to_str Jul = "07"
-> month_to_str Aug = "08"
-> month_to_str Sep = "09"
-> month_to_str Okt = "10"
-> month_to_str Nov = "11"
-> month_to_str Dez = "12"
-
 > day_to_int :: Tag -> Int
 > day_to_int I = 1
 > day_to_int II = 2
@@ -310,6 +263,7 @@ Nur Werte zwischen 0 und 99 fuer cent!
 > instance Num EuroCent where
 >   (+) s s' = (add_ec s s')
 >   (-) s s' = (diff_ec s s')
+>   fromInteger i = EC (fromIntegral(i `div` 100) :: Nat1) (fromIntegral(i `mod` 100) :: Nat1)
 
 > add_ec :: EuroCent -> EuroCent -> EuroCent
 > add_ec s s'
@@ -413,9 +367,9 @@ Aufgabe A.3
 > calculate_partner_credit :: KonsolidiertesKassabuch -> EuroCent -> EuroCent
 > calculate_partner_credit (KKB(x:xs)) res
 >   | length x /= 0 && null xs =
->       if is_k_credit v then res + (ec_netto v)
+>       if is_k_credit v then res + (ec_gutschrift v)
 >       else res
->   | is_k_credit v = calculate_partner_credit (KKB(xs)) (res + (ec_netto v))
+>   | is_k_credit v = calculate_partner_credit (KKB(xs)) (res + (ec_gutschrift v))
 >   | otherwise = calculate_partner_credit (KKB(xs)) res
 >   where
 >       (g,v) = x