diff --git a/src/uebung_klassen_Dog.py b/src/uebung_klassen_Dog.py
new file mode 100644
index 0000000..f3c0a58
--- /dev/null
+++ b/src/uebung_klassen_Dog.py
@@ -0,0 +1,41 @@
+class Hund:
+    anzahl_hunde = 0
+
+    def __init__(self, name: str, rasse: str, alter: int, gewicht: float):
+        self.name = name
+        self.rasse = rasse
+        self.alter = alter
+        self.gewicht = gewicht
+        Hund.anzahl_hunde += 1
+
+    def __repr__(self):
+        return (
+            f"Hund(name='{self.name}', rasse='{self.rasse}',"
+            f"alter={self.alter}, gewicht={self.gewicht}kg"
+        )
+
+    def __str__(self):
+        return f"{self.name} ist ein {self.alter}-jähriger {self.rasse}"
+
+    def bellen(self, anzahl=1):
+        print("Wuff!" * anzahl)
+        return
+
+    def geburtstag(self):
+        self.alter += 1
+        print(
+            f"Alles Gute zum Geburtstag, {self.name}! Du bist jetzt {self.alter} Jahre alt."
+        )
+        return
+
+    def ist_welpe(self):
+        return self.alter < 2
+
+
+hund1 = Hund("Bello", "Labrador", 3, 28.5)
+hund2 = Hund("BBarky", "Puddel", 4, 28.5)
+
+print(repr(hund1))
+print(hund1)
+print(hund1.__dict__)
+print(hund1.ist_welpe())
diff --git a/src/uebungen_klassen_cw.py b/src/uebungen_klassen_cw.py
new file mode 100644
index 0000000..cbca774
--- /dev/null
+++ b/src/uebungen_klassen_cw.py
@@ -0,0 +1,167 @@
+"""
+Codewars Kata:
+https://www.codewars.com/kata/54fe05c4762e2e3047000add
+"""
+
+
+class Ship:
+    def __init__(self, draft, crew):
+        self.draft = draft
+        self.crew = crew
+
+    def is_worth_it(self):
+        crew_weight = self.crew * 1.5
+        return self.draft - crew_weight > 20
+
+
+Titanic = Ship(15, 10)
+
+print(Titanic.is_worth_it())
+
+"""
+Codewars Kata:
+https://www.codewars.com/kata/528d36d7cc451cd7e4000339
+"""
+
+
+class Student:
+    all_students = []
+
+    def __init__(self, name, fives, tens, twenties):
+        self.name = name
+        self.fives = fives
+        self.tens = tens
+        self.twenties = twenties
+        Student.all_students.append(self)
+
+    def total_amount(self):
+        return self.fives * 5 + self.tens * 10 + self.twenties * 20
+
+
+richest_student = None
+multiple = False
+
+for s in Student.all_students:
+    if richest_student is None:
+        richest_student = s
+    elif s.total_amount() > richest_student.total_amount():
+        richest_student = s
+        multiple = False
+    elif s.total_amount() == richest_student.total_amount():
+        multiple = True
+
+if multiple:
+    print("all")
+else:
+    print(richest_student.name)
+
+"""
+Codewars Kata:
+https://www.codewars.com/kata/5a03af9606d5b65ff7000009
+"""
+
+
+class User:
+    def __init__(self, name: str, balance: int, checking_account: bool):
+        self.name = name
+        self.balance = balance
+        self.checking_account = checking_account
+
+    def withdraw(self, amount):
+        if amount > self.balance:
+            raise ValueError("overdraw")
+        self.balance -= amount
+        return f"{self.name} has {self.balance}."
+
+    def add_cash(self, amount):
+        self.balance += amount
+        return f"{self.name} has {self.balance}."
+
+    def check(self, issuer, amount):
+        if amount > issuer.balance:
+            raise ValueError("bad check")
+        if not issuer.checking_account:
+            raise ValueError("non checking-account")
+        self.balance += amount
+        issuer.balance -= amount
+        return f"{self.name} has {self.balance} and {issuer.name} has {issuer.balance}."
+
+
+"""
+Codewars Kata:
+https://www.codewars.com/kata/5941c545f5c394fef900000c
+"""
+
+
+class Warrior:
+    RANKS = [
+        ("Greatest", 100),
+        ("Master", 90),
+        ("Champion", 80),
+        ("Conqueror", 70),
+        ("Elite", 60),
+        ("Sage", 50),
+        ("Veteran", 40),
+        ("Warrior", 30),
+        ("Fighter", 20),
+        ("Novice", 10),
+        ("Pushover", 1),
+    ]
+
+    def __init__(self, level=1, rank="Pushover", experience=100, achievements=None):
+        self.level = level
+        self.rank = rank
+        self.experience = experience
+        self.achievements = achievements if achievements is not None else []
+
+    def battle(self, enemy):
+        if not enemy or enemy > 100:
+            return "Invalid level"
+
+        level_diff = enemy - self.level
+        rank_diff = (enemy // 10 + 1) - (self.level // 10 + 1)
+        if level_diff >= 5 and rank_diff >= 1:
+            return "You've been defeated"
+        else:
+            self.xp_won(level_diff)
+            if level_diff > 0:
+                return "An intense fight"
+            elif level_diff > -2:
+                return "A good fight"
+            else:
+                return "Easy fight"
+
+    def xp_won(self, diff: int):
+        xp_gained = 0
+        if diff == -1:
+            xp_gained = 5
+        elif diff == 0:
+            xp_gained = 10
+        elif diff > 0:
+            xp_gained = diff**2 * 20
+
+        if xp_gained:
+            self.add_xp(xp_gained)
+
+    def add_xp(self, xp_gained: int):
+        self.experience += xp_gained
+
+        if self.experience > 10000:
+            self.experience = 10000
+
+        if self.level != self.experience // 100:
+            self.level = self.experience // 100
+
+        for rank_name, max_level in self.RANKS:
+            if max_level <= self.level:
+                self.rank = rank_name
+                break
+
+    def training(self, training_arr):
+        description, xp_gained, min_level = training_arr
+        if self.level < min_level:
+            return "Not strong enough"
+        elif self.level >= min_level:
+            self.achievements.append(description)
+            self.add_xp(xp_gained)
+            return description