diff --git a/8_9_Atomkern/code/Atomkern/Atomkern.cpp b/8_9_Atomkern/code/Atomkern/Atomkern.cpp
index a6c97db..93815c9 100644
--- a/8_9_Atomkern/code/Atomkern/Atomkern.cpp
+++ b/8_9_Atomkern/code/Atomkern/Atomkern.cpp
@@ -1,4 +1,5 @@
 #include "Atomkern.h"
+#include <iostream>
 #include <ostream>
 
 Atomkern::Atomkern(std::string symbol, unsigned int masseZ,
@@ -11,7 +12,7 @@ unsigned int Atomkern::ordnungszahl() const { return ordnungs_zahl; }
 unsigned int Atomkern::massenzahl() const { return massen_zahl; }
 Atomkern &Atomkern::operator+=(const Atomkern &atom1) {
   massen_zahl += atom1.massenzahl();
-  ordnungs_zahl += atom1.massenzahl();
+  ordnungs_zahl += atom1.ordnungszahl();
   return *this;
 }
 Atomkern Atomkern::operator-(const Atomkern &atom1) {
@@ -20,7 +21,7 @@ Atomkern Atomkern::operator-(const Atomkern &atom1) {
 }
 Atomkern Atomkern::operator-=(const Atomkern &atom1) {
   massen_zahl -= atom1.massenzahl();
-  ordnungs_zahl -= atom1.massenzahl();
+  ordnungs_zahl -= atom1.ordnungszahl();
   return *this;
 }
 bool Atomkern::operator==(Atomkern const atom2) {
@@ -36,8 +37,7 @@ Atomkern operator*(int i, const Atomkern &atom1) {
                   atom1.ordnungszahl() * i);
 }
 std::ostream &operator<<(std::ostream &os, const Atomkern &atom) {
-  os << atom.symbol()
-     << "(" << atom.massenzahl()
-     << "," << atom.ordnungszahl() << ")";
+  os << atom.symbol() << "(" << atom.massenzahl() << "," << atom.ordnungszahl()
+     << ")";
   return os;
 }
diff --git a/8_9_Atomkern/code/Atomkern/build/8_Atomkern b/8_9_Atomkern/code/Atomkern/build/8_Atomkern
index 5bee237..2b8cafe 100755
Binary files a/8_9_Atomkern/code/Atomkern/build/8_Atomkern and b/8_9_Atomkern/code/Atomkern/build/8_Atomkern differ
diff --git a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o
index 5445523..0f88bcc 100644
Binary files a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o and b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o differ
diff --git a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o.d b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o.d
index 1cd18d0..02af735 100644
--- a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o.d
+++ b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o.d
@@ -143,4 +143,5 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o: \
  /usr/include/c++/16/bits/basic_ios.tcc \
  /usr/include/c++/16/bits/ostream_print.h \
  /usr/include/c++/16/bits/ostream.tcc /usr/include/string.h \
- /usr/include/strings.h
+ /usr/include/strings.h /usr/include/c++/16/iostream \
+ /usr/include/c++/16/istream /usr/include/c++/16/bits/istream.tcc
diff --git a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.internal b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.internal
index d81d52c..9e94515 100644
--- a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.internal
+++ b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.internal
@@ -123,6 +123,7 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o
  /usr/include/c++/16/bits/hash_bytes.h
  /usr/include/c++/16/bits/invoke.h
  /usr/include/c++/16/bits/ios_base.h
+ /usr/include/c++/16/bits/istream.tcc
  /usr/include/c++/16/bits/iterator_concepts.h
  /usr/include/c++/16/bits/locale_classes.h
  /usr/include/c++/16/bits/locale_classes.tcc
@@ -189,6 +190,8 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o
  /usr/include/c++/16/initializer_list
  /usr/include/c++/16/ios
  /usr/include/c++/16/iosfwd
+ /usr/include/c++/16/iostream
+ /usr/include/c++/16/istream
  /usr/include/c++/16/limits
  /usr/include/c++/16/new
  /usr/include/c++/16/numbers
diff --git a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.make b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.make
index d841449..33f72fc 100644
--- a/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.make
+++ b/8_9_Atomkern/code/Atomkern/build/CMakeFiles/8_Atomkern.dir/compiler_depend.make
@@ -121,6 +121,7 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o: /home/tobii/02_Uni/SS26/02_Objektorien
   /usr/include/c++/16/bits/hash_bytes.h \
   /usr/include/c++/16/bits/invoke.h \
   /usr/include/c++/16/bits/ios_base.h \
+  /usr/include/c++/16/bits/istream.tcc \
   /usr/include/c++/16/bits/iterator_concepts.h \
   /usr/include/c++/16/bits/locale_classes.h \
   /usr/include/c++/16/bits/locale_classes.tcc \
@@ -187,6 +188,8 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o: /home/tobii/02_Uni/SS26/02_Objektorien
   /usr/include/c++/16/initializer_list \
   /usr/include/c++/16/ios \
   /usr/include/c++/16/iosfwd \
+  /usr/include/c++/16/iostream \
+  /usr/include/c++/16/istream \
   /usr/include/c++/16/limits \
   /usr/include/c++/16/new \
   /usr/include/c++/16/numbers \
@@ -861,10 +864,6 @@ CMakeFiles/8_Atomkern.dir/main.cpp.o: /home/tobii/02_Uni/SS26/02_Objektorientier
 
 /usr/include/c++/16/sstream:
 
-/usr/include/c++/16/istream:
-
-/usr/include/c++/16/iostream:
-
 /usr/include/c++/16/bits/sstream.tcc:
 
 /usr/include/c++/16/bits/allocated_ptr.h:
@@ -917,6 +916,10 @@ CMakeFiles/8_Atomkern.dir/main.cpp.o: /home/tobii/02_Uni/SS26/02_Objektorientier
 
 /usr/include/c++/16/limits:
 
+/usr/include/c++/16/istream:
+
+/usr/include/c++/16/iostream:
+
 /usr/include/c++/16/initializer_list:
 
 /usr/include/c++/16/ext/type_traits.h:
@@ -1013,12 +1016,6 @@ CMakeFiles/8_Atomkern.dir/main.cpp.o: /home/tobii/02_Uni/SS26/02_Objektorientier
 
 /usr/include/c++/16/bits/move.h:
 
-/usr/include/c++/16/bits/istream.tcc:
-
-/usr/include/c++/16/cerrno:
-
-/usr/include/bits/types/__FILE.h:
-
 /usr/include/bits/setjmp.h:
 
 /usr/include/bits/types/struct___jmp_buf_tag.h:
@@ -1235,6 +1232,10 @@ CMakeFiles/8_Atomkern.dir/Atomkern.cpp.o:
 
 /usr/include/c++/16/bits/localefwd.h:
 
+/usr/include/c++/16/bits/memory_resource.h:
+
+/usr/include/bits/types/sigset_t.h:
+
 /usr/include/endian.h:
 
 /usr/include/c++/16/cwctype:
@@ -1275,10 +1276,6 @@ CMakeFiles/8_Atomkern.dir/PrueffolgeAtomkern.cpp.o:
 
 /usr/include/c++/16/bits/ios_base.h:
 
-/usr/include/bits/types/sigset_t.h:
-
-/usr/include/c++/16/bits/memory_resource.h:
-
 /usr/include/c++/16/string:
 
 /usr/include/bits/timesize.h:
@@ -1353,6 +1350,12 @@ CMakeFiles/8_Atomkern.dir/PrueffolgeAtomkern.cpp.o:
 
 /usr/include/c++/16/bits/hash_bytes.h:
 
+/usr/include/c++/16/cerrno:
+
+/usr/include/bits/types/__FILE.h:
+
+/usr/include/c++/16/bits/istream.tcc:
+
 /usr/include/c++/16/bits/new_throw.h:
 
 /usr/include/c++/16/bits/locale_classes.h: