diff --git a/src/fraction_simplifier.py b/src/fraction_simplifier.py
new file mode 100644
index 00000000..c61658cb
--- /dev/null
+++ b/src/fraction_simplifier.py
@@ -0,0 +1,46 @@
+from math import gcd
+
+def simplify_fraction(numerator: int, denominator: int) -> tuple:
+    """
+    Simplify a fraction to its lowest terms.
+    
+    Args:
+        numerator (int): The numerator of the fraction
+        denominator (int): The denominator of the fraction
+    
+    Returns:
+        tuple: A tuple containing the simplified numerator and denominator
+    
+    Raises:
+        ValueError: If denominator is zero
+        TypeError: If inputs are not integers
+    """
+    # Validate inputs
+    if not isinstance(numerator, int) or not isinstance(denominator, int):
+        raise TypeError("Numerator and denominator must be integers")
+    
+    # Check for zero denominator
+    if denominator == 0:
+        raise ValueError("Denominator cannot be zero")
+    
+    # Handle special case of zero numerator
+    if numerator == 0:
+        return (0, 1)
+    
+    # Determine the sign 
+    sign = 1
+    if numerator * denominator < 0:
+        sign = -1
+    
+    # Work with absolute values
+    numerator = abs(numerator)
+    denominator = abs(denominator)
+    
+    # Find the greatest common divisor
+    divisor = gcd(numerator, denominator)
+    
+    # Simplify the fraction
+    simplified_numerator = sign * (numerator // divisor)
+    simplified_denominator = denominator // divisor
+    
+    return (simplified_numerator, simplified_denominator)
\ No newline at end of file
diff --git a/src/gcd_calculator.py b/src/gcd_calculator.py
new file mode 100644
index 00000000..b68ae915
--- /dev/null
+++ b/src/gcd_calculator.py
@@ -0,0 +1,60 @@
+from src.prime_factorization import prime_factorization
+
+def gcd_using_prime_factors(a, b):
+    """
+    Calculate the Greatest Common Divisor (GCD) of two numbers using prime factorization.
+    
+    This function computes the GCD by finding the common prime factors between 
+    the two input numbers and multiplying them.
+    
+    Args:
+        a (int): First positive integer.
+        b (int): Second positive integer.
+    
+    Returns:
+        int: The Greatest Common Divisor of a and b.
+    
+    Raises:
+        ValueError: If either input is not a positive integer.
+    """
+    # Validate inputs
+    if not isinstance(a, int) or not isinstance(b, int):
+        raise ValueError("Inputs must be integers")
+    
+    if a <= 0 or b <= 0:
+        raise ValueError("Inputs must be positive integers")
+    
+    # Special case: if either number is 1, GCD is 1
+    if a == 1 or b == 1:
+        return 1
+    
+    # Get prime factorizations of both numbers
+    a_factors = prime_factorization(a)
+    b_factors = prime_factorization(b)
+    
+    # Find common prime factors
+    gcd_factors = []
+    a_factor_count = {}
+    b_factor_count = {}
+    
+    # Count occurrences of prime factors
+    for factor in a_factors:
+        a_factor_count[factor] = a_factor_count.get(factor, 0) + 1
+    
+    for factor in b_factors:
+        b_factor_count[factor] = b_factor_count.get(factor, 0) + 1
+    
+    # Determine common prime factors with their minimum occurrence
+    for factor in set(a_factor_count.keys()) & set(b_factor_count.keys()):
+        common_count = min(a_factor_count[factor], b_factor_count[factor])
+        gcd_factors.extend([factor] * common_count)
+    
+    # Calculate GCD by multiplying common prime factors
+    if not gcd_factors:
+        return 1  # If no common factors, GCD is 1
+    
+    gcd = 1
+    for factor in gcd_factors:
+        gcd *= factor
+    
+    return gcd
\ No newline at end of file
diff --git a/src/lcm_calculator.py b/src/lcm_calculator.py
new file mode 100644
index 00000000..986648b9
--- /dev/null
+++ b/src/lcm_calculator.py
@@ -0,0 +1,56 @@
+from src.gcd_calculator import gcd_using_prime_factors as gcd
+
+def lcm(a: int, b: int) -> int:
+    """
+    Calculate the Least Common Multiple (LCM) of two integers.
+    
+    The LCM is calculated using the formula: LCM(a,b) = |a * b| / GCD(a,b)
+    
+    Args:
+        a (int): First integer
+        b (int): Second integer
+    
+    Returns:
+        int: The Least Common Multiple of a and b
+    
+    Raises:
+        ValueError: If either input is not a positive integer
+        TypeError: If inputs are not integers
+    """
+    # Type checking
+    if not isinstance(a, int) or not isinstance(b, int):
+        raise TypeError("Inputs must be integers")
+    
+    # Check for positive integers
+    if a <= 0 or b <= 0:
+        raise ValueError("Inputs must be positive integers")
+    
+    # Calculate LCM using the formula: LCM(a,b) = |a * b| / GCD(a,b)
+    return abs(a * b) // gcd(a, b)
+
+def lcm_multiple(*args: int) -> int:
+    """
+    Calculate the Least Common Multiple of multiple integers.
+    
+    Args:
+        *args (int): Variable number of positive integers
+    
+    Returns:
+        int: The Least Common Multiple of all input integers
+    
+    Raises:
+        ValueError: If no arguments are provided or any argument is not a positive integer
+        TypeError: If any input is not an integer
+    """
+    # Check if arguments are provided
+    if len(args) == 0:
+        raise ValueError("At least one integer is required")
+    
+    # Initialize result with the first number
+    result = args[0]
+    
+    # Calculate LCM for all subsequent numbers
+    for num in args[1:]:
+        result = lcm(result, num)
+    
+    return result
\ No newline at end of file
diff --git a/src/prime_checker.py b/src/prime_checker.py
new file mode 100644
index 00000000..0b9ce838
--- /dev/null
+++ b/src/prime_checker.py
@@ -0,0 +1,28 @@
+def is_prime(number):
+    """
+    Check if a given number is prime.
+    
+    Args:
+        number (int): The number to check for primality.
+    
+    Returns:
+        bool: True if the number is prime, False otherwise.
+    
+    Raises:
+        ValueError: If the input is not a positive integer.
+    """
+    # Validate input
+    if not isinstance(number, int):
+        raise ValueError("Input must be an integer")
+    
+    # Handle edge cases
+    if number < 2:
+        return False
+    
+    # Check for primality using trial division
+    # Only need to check up to the square root of the number
+    for i in range(2, int(number**0.5) + 1):
+        if number % i == 0:
+            return False
+    
+    return True
\ No newline at end of file
diff --git a/src/prime_factorization.py b/src/prime_factorization.py
new file mode 100644
index 00000000..040f69e9
--- /dev/null
+++ b/src/prime_factorization.py
@@ -0,0 +1,47 @@
+def prime_factorization(n):
+    """
+    Compute the prime factorization of a given positive integer.
+    
+    Args:
+        n (int): A positive integer to factorize.
+    
+    Returns:
+        list: A list of prime factors of the input number.
+    
+    Raises:
+        ValueError: If the input is not a positive integer.
+    """
+    # Validate input
+    if not isinstance(n, int):
+        raise ValueError("Input must be an integer")
+    
+    if n <= 0:
+        raise ValueError("Input must be a positive integer")
+    
+    # Special case for 1
+    if n == 1:
+        return []
+    
+    # List to store prime factors
+    factors = []
+    
+    # Handle 2 as a special case first
+    while n % 2 == 0:
+        factors.append(2)
+        n //= 2
+    
+    # Check for odd prime factors
+    factor = 3
+    while factor * factor <= n:
+        # If factor divides n, add it to factors
+        while n % factor == 0:
+            factors.append(factor)
+            n //= factor
+        # Move to next potential prime factor
+        factor += 2
+    
+    # If n is a prime number greater than 2
+    if n > 2:
+        factors.append(n)
+    
+    return factors
\ No newline at end of file
diff --git a/tests/test_fraction_simplifier.py b/tests/test_fraction_simplifier.py
new file mode 100644
index 00000000..8bc3dbcf
--- /dev/null
+++ b/tests/test_fraction_simplifier.py
@@ -0,0 +1,39 @@
+import pytest
+from src.fraction_simplifier import simplify_fraction
+
+def test_simplify_positive_fraction():
+    """Test simplifying a positive fraction"""
+    assert simplify_fraction(4, 6) == (2, 3)
+
+def test_simplify_negative_fraction():
+    """Test simplifying a negative fraction"""
+    assert simplify_fraction(-4, 6) == (-2, 3)
+    assert simplify_fraction(4, -6) == (-2, 3)
+    assert simplify_fraction(-4, -6) == (2, 3)
+
+def test_zero_numerator():
+    """Test fraction with zero numerator"""
+    assert simplify_fraction(0, 5) == (0, 1)
+    assert simplify_fraction(0, -5) == (0, 1)
+
+def test_already_simplified_fraction():
+    """Test a fraction that is already in its simplest form"""
+    assert simplify_fraction(5, 7) == (5, 7)
+
+def test_large_fraction():
+    """Test simplifying a larger fraction"""
+    assert simplify_fraction(48, 180) == (4, 15)
+
+def test_zero_denominator():
+    """Test that zero denominator raises a ValueError"""
+    with pytest.raises(ValueError, match="Denominator cannot be zero"):
+        simplify_fraction(1, 0)
+
+def test_invalid_input_types():
+    """Test that non-integer inputs raise a TypeError"""
+    with pytest.raises(TypeError, match="Numerator and denominator must be integers"):
+        simplify_fraction(1.5, 2)
+    with pytest.raises(TypeError, match="Numerator and denominator must be integers"):
+        simplify_fraction(1, "2")
+    with pytest.raises(TypeError, match="Numerator and denominator must be integers"):
+        simplify_fraction("1", 2)
\ No newline at end of file
diff --git a/tests/test_gcd_calculator.py b/tests/test_gcd_calculator.py
new file mode 100644
index 00000000..05280493
--- /dev/null
+++ b/tests/test_gcd_calculator.py
@@ -0,0 +1,44 @@
+import pytest
+from src.gcd_calculator import gcd_using_prime_factors
+
+def test_gcd_basic_cases():
+    """Test basic GCD calculations."""
+    assert gcd_using_prime_factors(48, 18) == 6
+    assert gcd_using_prime_factors(54, 24) == 6
+    assert gcd_using_prime_factors(100, 75) == 25
+
+def test_gcd_coprime_numbers():
+    """Test GCD of coprime numbers."""
+    assert gcd_using_prime_factors(7, 13) == 1
+    assert gcd_using_prime_factors(11, 17) == 1
+
+def test_gcd_same_number():
+    """Test GCD when both numbers are the same."""
+    assert gcd_using_prime_factors(12, 12) == 12
+    assert gcd_using_prime_factors(17, 17) == 17
+
+def test_gcd_one_is_multiple():
+    """Test GCD when one number is a multiple of the other."""
+    assert gcd_using_prime_factors(24, 8) == 8
+    assert gcd_using_prime_factors(8, 24) == 8
+
+def test_gcd_one_is_one():
+    """Test GCD when one number is 1."""
+    assert gcd_using_prime_factors(1, 15) == 1
+    assert gcd_using_prime_factors(15, 1) == 1
+
+def test_gcd_invalid_inputs():
+    """Test error handling for invalid inputs."""
+    with pytest.raises(ValueError, match="Inputs must be integers"):
+        gcd_using_prime_factors(10.5, 15)
+    
+    with pytest.raises(ValueError, match="Inputs must be positive integers"):
+        gcd_using_prime_factors(0, 15)
+    
+    with pytest.raises(ValueError, match="Inputs must be positive integers"):
+        gcd_using_prime_factors(10, -5)
+
+def test_gcd_large_numbers():
+    """Test GCD calculation for larger numbers."""
+    assert gcd_using_prime_factors(1260, 1680) == 420
+    assert gcd_using_prime_factors(123456, 789012) == 12
\ No newline at end of file
diff --git a/tests/test_lcm_calculator.py b/tests/test_lcm_calculator.py
new file mode 100644
index 00000000..c84c9bec
--- /dev/null
+++ b/tests/test_lcm_calculator.py
@@ -0,0 +1,51 @@
+import pytest
+from src.lcm_calculator import lcm, lcm_multiple
+
+def test_lcm_basic_functionality():
+    """Test basic LCM calculations"""
+    assert lcm(4, 6) == 12
+    assert lcm(21, 6) == 42
+    assert lcm(17, 5) == 85
+
+def test_lcm_same_number():
+    """Test LCM when both numbers are the same"""
+    assert lcm(7, 7) == 7
+    assert lcm(13, 13) == 13
+
+def test_lcm_one_is_multiple():
+    """Test LCM when one number is a multiple of the other"""
+    assert lcm(8, 4) == 8
+    assert lcm(15, 5) == 15
+
+def test_lcm_coprime():
+    """Test LCM of coprime numbers"""
+    assert lcm(7, 11) == 77
+    assert lcm(13, 17) == 221
+
+def test_lcm_multiple_integers():
+    """Test LCM calculation with multiple integers"""
+    assert lcm_multiple(2, 3, 4) == 12
+    assert lcm_multiple(3, 4, 6) == 12
+    assert lcm_multiple(2, 3, 5, 7) == 210
+
+def test_lcm_error_handling():
+    """Test error handling for invalid inputs"""
+    # Test non-integer inputs
+    with pytest.raises(TypeError):
+        lcm(4.5, 6)
+    with pytest.raises(TypeError):
+        lcm("4", 6)
+    
+    # Test non-positive integer inputs
+    with pytest.raises(ValueError):
+        lcm(0, 6)
+    with pytest.raises(ValueError):
+        lcm(-4, 6)
+    
+    # Test multiple LCM with no arguments or invalid inputs
+    with pytest.raises(ValueError):
+        lcm_multiple()
+    with pytest.raises(TypeError):
+        lcm_multiple(2, 3, "4")
+    with pytest.raises(ValueError):
+        lcm_multiple(0, 3, 4)
\ No newline at end of file
diff --git a/tests/test_prime_checker.py b/tests/test_prime_checker.py
new file mode 100644
index 00000000..f0317059
--- /dev/null
+++ b/tests/test_prime_checker.py
@@ -0,0 +1,37 @@
+import pytest
+from src.prime_checker import is_prime
+
+def test_prime_numbers():
+    """Test known prime numbers"""
+    prime_numbers = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
+    for num in prime_numbers:
+        assert is_prime(num) is True, f"{num} should be prime"
+
+def test_non_prime_numbers():
+    """Test known non-prime numbers"""
+    non_prime_numbers = [0, 1, 4, 6, 8, 9, 10, 12, 14, 15]
+    for num in non_prime_numbers:
+        assert is_prime(num) is False, f"{num} should not be prime"
+
+def test_large_prime():
+    """Test a large prime number"""
+    assert is_prime(104729) is True, "104729 is a prime number"
+
+def test_large_non_prime():
+    """Test a large non-prime number"""
+    assert is_prime(104730) is False, "104730 is not a prime number"
+
+def test_negative_numbers():
+    """Test that negative numbers are not prime"""
+    assert is_prime(-7) is False, "Negative numbers should not be prime"
+
+def test_invalid_input():
+    """Test that invalid inputs raise a ValueError"""
+    with pytest.raises(ValueError):
+        is_prime(3.14)
+    
+    with pytest.raises(ValueError):
+        is_prime("not a number")
+    
+    with pytest.raises(ValueError):
+        is_prime(None)
\ No newline at end of file
diff --git a/tests/test_prime_factorization.py b/tests/test_prime_factorization.py
new file mode 100644
index 00000000..4839fc87
--- /dev/null
+++ b/tests/test_prime_factorization.py
@@ -0,0 +1,39 @@
+import pytest
+from src.prime_factorization import prime_factorization
+
+def test_prime_factorization_basic():
+    """Test basic prime factorization"""
+    assert prime_factorization(12) == [2, 2, 3]
+    assert prime_factorization(15) == [3, 5]
+    assert prime_factorization(100) == [2, 2, 5, 5]
+
+def test_prime_factorization_prime_number():
+    """Test prime factorization of prime numbers"""
+    assert prime_factorization(7) == [7]
+    assert prime_factorization(11) == [11]
+    assert prime_factorization(17) == [17]
+
+def test_prime_factorization_special_cases():
+    """Test special cases"""
+    assert prime_factorization(1) == []
+    assert prime_factorization(2) == [2]
+
+def test_prime_factorization_large_number():
+    """Test prime factorization of a larger number"""
+    assert prime_factorization(84) == [2, 2, 3, 7]
+
+def test_prime_factorization_invalid_inputs():
+    """Test error handling for invalid inputs"""
+    with pytest.raises(ValueError, match="Input must be an integer"):
+        prime_factorization("12")
+    
+    with pytest.raises(ValueError, match="Input must be a positive integer"):
+        prime_factorization(0)
+    
+    with pytest.raises(ValueError, match="Input must be a positive integer"):
+        prime_factorization(-5)
+
+def test_prime_factorization_large_prime():
+    """Test prime factorization of a large prime number"""
+    large_prime = 104729  # A large prime number
+    assert prime_factorization(large_prime) == [104729]
\ No newline at end of file