diff --git a/1.py b/1.py
new file mode 100644
index 0000000..90c3e09
--- /dev/null
+++ b/1.py
@@ -0,0 +1,19 @@
+def double(number):
+    return number * 3
+
+print(double(10))
+
+# Here the name of the function is double but on line 3 it returns the triple of the a given number
+# Fix version
+
+def triple(number):
+    return number * 3
+
+print(triple(10))
+
+# or
+
+def double(number):
+    return number * 2
+
+print(double(10))
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diff --git a/2.py b/2.py
new file mode 100644
index 0000000..3d37411
--- /dev/null
+++ b/2.py
@@ -0,0 +1,41 @@
+from typing import List, Dict, Union
+
+def open_account(balances: dict[str, int], name: str, amount: Union[int, float, str]) -> None :
+    if isinstance(amount, str) and amount.startswith("£"):
+        pounds, pence = map(int, amount[1:].split("."))
+        amount = pounds * 100 + pence
+    elif isinstance(amount, float):
+        amount = int(round(amount * 100))
+    elif isinstance(amount, int):
+        pass
+    else:
+        raise ValueError("Unsupported amount format")
+    balances[name] = amount
+
+def sum_balances(accounts: Dict[str, int]) -> int:
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_str(total_pence: int) -> str:
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = int(total_pence / 100)
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+open_account(balances,"Tobi", 9.13)
+open_account(balances,"Olya", "£7.13")
+
+total_pence:int = sum_balances(balances)
+total_string: str = format_pence_as_str(total_pence)
+
+print(f"The bank accounts total {total_string}")
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diff --git a/3.py b/3.py
new file mode 100644
index 0000000..9e548ef
--- /dev/null
+++ b/3.py
@@ -0,0 +1,27 @@
+class Person:
+    def __init__(self, name: str, age: int, preferred_operating_system: str):
+        self.name = name
+        self.age = age
+        self.preferred_operating_system = preferred_operating_system
+
+imran = Person("Imran", 22, "Ubuntu")
+print(imran.name)
+print(imran.address)
+
+eliza = Person("Eliza", 34, "Arch Linux")
+print(eliza.name)
+print(eliza.address)
+
+#  error: "Person" has no attribute "address" 
+#  error: "Person" has no attribute "address" 
+
+def is_adult(person: Person) -> bool:
+    return person.age >= 18
+
+print(is_adult(imran))
+# no error
+
+
+def get_city(person: Person) -> str:
+    return person.location
+#person has no attribute location.
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diff --git a/4.py b/4.py
new file mode 100644
index 0000000..a28d2c8
--- /dev/null
+++ b/4.py
@@ -0,0 +1,18 @@
+from datetime import date
+
+class Person:
+    def __init__(self, name: str, date_of_birth: date, preferred_operating_system: str):
+        self.name = name
+        self.date_of_birth = date_of_birth
+        self.preferred_operating_system = preferred_operating_system
+
+def is_adult(person: Person) -> bool:
+    today = date.today()
+    dob = person.date_of_birth
+    age = today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
+    return age >= 18
+
+imran_dob = date(2003, 9, 10)
+imran = Person("Imran", imran_dob, "Ubuntu")
+
+print(is_adult(imran))  # True
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diff --git a/5.py b/5.py
new file mode 100644
index 0000000..9e3af7a
--- /dev/null
+++ b/5.py
@@ -0,0 +1,19 @@
+from dataclasses import dataclass
+from datetime import date
+
+@dataclass
+class Person:
+    name: str
+    date_of_birth: date
+    preferred_operating_system: str
+
+    def is_adult(self) -> bool:
+        today = date.today()
+        dob = self.date_of_birth
+        age = today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
+        return age >= 18
+
+
+imran = Person(name="Imran", date_of_birth=date(2003, 9, 10), preferred_operating_system="Ubuntu")
+
+print(imran.is_adult())  # Output: True
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diff --git a/6.py b/6.py
new file mode 100644
index 0000000..28057ed
--- /dev/null
+++ b/6.py
@@ -0,0 +1,27 @@
+from dataclasses import dataclass
+from datetime import date
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    date_of_birth: date
+    children: List["Person"]
+
+    @property
+    def age(self) -> int:
+        today = date.today()
+        dob = self.date_of_birth
+        return today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
+
+def print_family_tree(person: Person, indent: int = 0) -> None:
+    spacer = "  " * indent
+    print(f"{spacer}{person.name} (Age: {person.age})")
+    for child in person.children:
+        print_family_tree(child, indent + 1)
+
+fatma = Person(name="Fatma", date_of_birth=date(2012, 5, 14), children=[])
+aisha = Person(name="Aisha", date_of_birth=date(2015, 8, 3), children=[])
+imran = Person(name="Imran", date_of_birth=date(1985, 2, 20), children=[fatma, aisha])
+
+print_family_tree(imran)
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diff --git a/7.py b/7.py
new file mode 100644
index 0000000..265cac4
--- /dev/null
+++ b/7.py
@@ -0,0 +1,41 @@
+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_systems: List[str]
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_systems: List[str]
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    possible_laptops = []
+    for laptop in laptops:
+        if laptop.operating_systems == person.preferred_operating_systems:
+            possible_laptops.append(laptop)
+    return possible_laptops
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_systems=["Ubuntu"]),
+    Person(name="Eliza", age=34, preferred_operating_systems=["Arch Linux"]),
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_systems=["Arch Linux"]),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_systems=["Ubuntu"]),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_systems=["ubuntu"]),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_systems=["macOS"]),
+]
+
+for person in people:
+    possible_laptops = find_possible_laptops(laptops, person)
+    print(f"Possible laptops for {person.name}: {possible_laptops}")
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diff --git a/8.py b/8.py
new file mode 100644
index 0000000..a4a76e1
--- /dev/null
+++ b/8.py
@@ -0,0 +1,88 @@
+import sys
+from dataclasses import dataclass
+from enum import Enum
+from typing import List
+from collections import Counter
+
+
+class OperatingSystem(Enum):
+    MACOS = "macOS"
+    ARCH = "Arch Linux"
+    UBUNTU = "Ubuntu"
+
+    @classmethod
+    def from_string(cls, s: str):
+        for os in cls:
+            if os.value.lower() == s.lower():
+                return os
+        raise ValueError(f"Unsupported operating system: {s}")
+
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_system: OperatingSystem
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    return [laptop for laptop in laptops if laptop.operating_system == person.preferred_operating_system]
+
+
+def main():
+    # Existing inventory
+    laptops = [
+        Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system=OperatingSystem.ARCH),
+        Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+    ]
+
+    # Read and validate user input
+    try:
+        name = input("Enter your name: ").strip()
+        if not name:
+            raise ValueError("Name cannot be empty.")
+
+        age_input = input("Enter your age: ").strip()
+        age = int(age_input)
+        if age <= 0:
+            raise ValueError("Age must be a positive integer.")
+
+        print("Available operating systems:")
+        for os in OperatingSystem:
+            print(f"- {os.value}")
+        os_input = input("Enter your preferred operating system: ").strip()
+        preferred_os = OperatingSystem.from_string(os_input)
+
+    except ValueError as e:
+        print(f"Error: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    # Create the person
+    person = Person(name=name, age=age, preferred_operating_system=preferred_os)
+
+    # Check availability
+    possible_laptops = find_possible_laptops(laptops, person)
+    print(f"\nThere are {len(possible_laptops)} laptops available with {preferred_os.value}.")
+
+    # Count OS distribution
+    os_counts = Counter(laptop.operating_system for laptop in laptops)
+    most_common_os, most_common_count = os_counts.most_common(1)[0]
+
+    if most_common_os != preferred_os and most_common_count > len(possible_laptops):
+        print(f"Note: There are more laptops available with {most_common_os.value} ({most_common_count} total).")
+        print(f"If you're willing to accept {most_common_os.value}, you're more likely to get a laptop.")
+
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file
diff --git a/9.py b/9.py
new file mode 100644
index 0000000..ed7a4f1
--- /dev/null
+++ b/9.py
@@ -0,0 +1,49 @@
+class Parent:
+    def __init__(self, first_name: str, last_name: str):
+        self.first_name = first_name
+        self.last_name = last_name
+
+    def get_name(self) -> str:
+        return f"{self.first_name} {self.last_name}"
+
+
+class Child(Parent):
+    def __init__(self, first_name: str, last_name: str):
+        super().__init__(first_name, last_name)
+        self.previous_last_names = []
+
+    def change_last_name(self, last_name) -> None:
+        self.previous_last_names.append(self.last_name)
+        self.last_name = last_name
+
+    def get_full_name(self) -> str:
+        suffix = ""
+        if len(self.previous_last_names) > 0:
+            suffix = f" (née {self.previous_last_names[0]})"
+        return f"{self.first_name} {self.last_name}{suffix}"
+
+person1 = Child("Elizaveta", "Alekseeva")
+print(person1.get_name())
+print(person1.get_full_name())
+person1.change_last_name("Tyurina")
+print(person1.get_name())
+print(person1.get_full_name())
+
+person2 = Parent("Elizaveta", "Alekseeva")
+print(person2.get_name())
+#print(person2.get_full_name())
+#person2.change_last_name("Tyurina")
+print(person2.get_name())
+#print(person2.get_full_name())
+
+
+#W/O commenting output:
+#Elizaveta Alekseeva
+#Elizaveta Alekseeva
+#Elizaveta Tyurina
+#Elizaveta Alekseeva
+#Elizaveta Tyurina (née Alekseeva)
+#Traceback (most recent call last):
+#  File "/Users/Module-Decomposition/prep_exercises/exercise9inheritance.py", line 34, in <module>
+#    print(person2.get_full_name())
+#AttributeError: 'Parent' object has no attribute 'get_full_name'
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