diff --git a/src/calculator.py b/src/calculator.py
index e392fe0..e41739a 100644
--- a/src/calculator.py
+++ b/src/calculator.py
@@ -6,15 +6,3 @@ def add(left: int, right: int) -> int:
 
 def subtract(left: int, right: int) -> int:
     return left - right
-
-
-def modulo(left: int, right: int) -> int:
-    if right == 0:
-        raise ValueError('modulo by zero')
-    return left % right
-
-
-def gcd(left: int, right: int) -> int:
-    while right:
-        left, right = right, left % right
-    return abs(left)
diff --git a/tests/__pycache__/test_calculator.cpython-315.pyc b/tests/__pycache__/test_calculator.cpython-315.pyc
deleted file mode 100644
index 328beb2..0000000
Binary files a/tests/__pycache__/test_calculator.cpython-315.pyc and /dev/null differ
diff --git a/tests/test_calculator.py b/tests/test_calculator.py
deleted file mode 100644
index f05e23b..0000000
--- a/tests/test_calculator.py
+++ /dev/null
@@ -1,58 +0,0 @@
-# retoor <retoor@molodetz.nl>
-
-import unittest
-
-from src.calculator import add, subtract, multiply, divide
-
-
-class TestCalculator(unittest.TestCase):
-
-    def test_add(self) -> None:
-        self.assertEqual(add(2, 3), 5)
-
-    def test_subtract(self) -> None:
-        self.assertEqual(subtract(5, 3), 2)
-
-    def test_multiply_positive(self) -> None:
-        self.assertEqual(multiply(2, 3), 6)
-
-    def test_multiply_negative_left(self) -> None:
-        self.assertEqual(multiply(-2, 3), -6)
-
-    def test_multiply_negative_right(self) -> None:
-        self.assertEqual(multiply(2, -3), -6)
-
-    def test_multiply_both_negative(self) -> None:
-        self.assertEqual(multiply(-2, -3), 6)
-
-    def test_multiply_zero_left(self) -> None:
-        self.assertEqual(multiply(0, 5), 0)
-
-    def test_multiply_zero_right(self) -> None:
-        self.assertEqual(multiply(5, 0), 0)
-
-    def test_multiply_both_zero(self) -> None:
-        self.assertEqual(multiply(0, 0), 0)
-
-    def test_divide_positive(self) -> None:
-        self.assertEqual(divide(6, 3), 2)
-
-    def test_divide_negative_left(self) -> None:
-        self.assertEqual(divide(-6, 3), -2)
-
-    def test_divide_negative_right(self) -> None:
-        self.assertEqual(divide(6, -3), -2)
-
-    def test_divide_both_negative(self) -> None:
-        self.assertEqual(divide(-6, -3), 2)
-
-    def test_divide_floor(self) -> None:
-        self.assertEqual(divide(7, 3), 2)
-
-    def test_divide_zero_numerator(self) -> None:
-        self.assertEqual(divide(0, 5), 0)
-
-    def test_divide_by_zero(self) -> None:
-        with self.assertRaises(ValueError) as cm:
-            divide(5, 0)
-        self.assertEqual(str(cm.exception), 'division by zero')