diff --git a/brain_games/game_const.py b/brain_games/game_const.py
index cefe25b..03a4147 100644
--- a/brain_games/game_const.py
+++ b/brain_games/game_const.py
@@ -8,3 +8,4 @@
 ROUND_COUNT = 3
 GREETING = "Welcome to the Brain Games!\nMay I have your name?"
 PROGRESSION_LENGTH = 10
+OPERATORS = ["+", "-", "*"]
diff --git a/brain_games/games/calc_engine.py b/brain_games/games/calc_engine.py
index d2e8690..63705bb 100644
--- a/brain_games/games/calc_engine.py
+++ b/brain_games/games/calc_engine.py
@@ -1,29 +1,15 @@
 import random
-import prompt
-from brain_games.game_const import GAME_INSTRUCTIONS, ROUND_COUNT, GREETING
+from brain_games.game_const import GAME_INSTRUCTIONS, OPERATORS
+from brain_games.game_engine import run_game
 
 
-def math_calc():
-    player_name = prompt.string(f"{GREETING} ")
-    print(f'Hello, {player_name}!'
-          f'\n{GAME_INSTRUCTIONS["calc"]}')
-    for _ in range(ROUND_COUNT):
-        first_num = random.randint(1, 10)
-        second_num = random.randint(1, 10)
-        calc_sign_list = ["+", "-", "*"]
-        calc_sign_random = random.choice(calc_sign_list)
-        expression = f"{first_num} {calc_sign_random} {second_num}"
-        correct_answer = eval(expression)
+def math_expression_and_result():
+    first_num, second_num = random.randint(1, 10), random.randint(1, 10)
+    operator = random.choice(OPERATORS)
+    expression = f"{first_num} {operator} {second_num}"
+    result = eval(expression)
+    return expression, str(result)
 
-        player_answer = prompt.string(f"\nQuestion: {expression}"
-                                      f"\nAnswer: ")
 
-        if correct_answer == int(player_answer):
-            print("Correct!")
-        else:
-            print(f"'{player_answer}' is wrong answer ;(. "
-                  f"Correct answer was {correct_answer}.\n"
-                  f"Let's try again, {player_name}!")
-            return
-
-    return print(f"Congratulations, {player_name}!")
+def run_calc_engine_game():
+    run_game(math_expression_and_result, GAME_INSTRUCTIONS['calc'])
diff --git a/brain_games/games/even_engine.py b/brain_games/games/even_engine.py
index 537631b..476cc87 100644
--- a/brain_games/games/even_engine.py
+++ b/brain_games/games/even_engine.py
@@ -1,26 +1,13 @@
-import prompt
 import random
-from brain_games.game_const import GAME_INSTRUCTIONS, ROUND_COUNT, GREETING
+from brain_games.game_const import GAME_INSTRUCTIONS
+from brain_games.game_engine import run_game
 
 
-def even_game():
-    player_name = prompt.string(f"{GREETING} ")
-    print(f'Hello, {player_name}!'
-          f'\n{GAME_INSTRUCTIONS["even"]}')
+def number_and_even_answer():
+    num = random.randint(1, 30)
+    correct_answer = 'yes' if num % 2 == 0 else 'no'
+    return num, correct_answer
 
-    for _ in range(ROUND_COUNT):
-        num = random.randint(1, 31)
-        correct_answer = 'yes' if num % 2 == 0 else 'no'
 
-        player_answer = prompt.string(f'Question: {num}'
-                                      f'\nAnswer: ').lower()
-
-        if correct_answer == player_answer:
-            print("Correct!")
-        else:
-            print(f"'{player_answer}' is wrong answer ;(. "
-                  f"Correct answer was {correct_answer}.\n"
-                  f"Let's try again, {player_name}!")
-            return
-
-    return print(f"Congratulations, {player_name}!")
+def run_even_engine_game():
+    run_game(number_and_even_answer, GAME_INSTRUCTIONS['even'])
diff --git a/brain_games/games/gcd_engine.py b/brain_games/games/gcd_engine.py
index cbd0360..bdc4489 100644
--- a/brain_games/games/gcd_engine.py
+++ b/brain_games/games/gcd_engine.py
@@ -1,28 +1,15 @@
+import math
 import random
-import prompt
-from math import gcd
-from brain_games.game_const import GAME_INSTRUCTIONS, ROUND_COUNT, GREETING
+from brain_games.game_engine import run_game
+from brain_games.game_const import GAME_INSTRUCTIONS
 
 
-def func_gcd():
-    player_name = prompt.string(f"{GREETING} ")
-    print(f"Hello, {player_name}!"
-          f"\n{GAME_INSTRUCTIONS['gcd']}")
-    for _ in range(ROUND_COUNT):
-        first_num = random.randint(1, 100)
-        second_num = random.randint(1, 55)
+def func_numbers_and_gcd():
+    first_num, second_num = random.randint(1, 50), random.randint(1, 30)
+    gcd_answer = math.gcd(first_num, second_num)
+    numbers = f"{first_num} {second_num}"
+    return numbers, str(gcd_answer)
 
-        correct_answer = gcd(first_num, second_num)
 
-        player_answer = prompt.string(f"\nQuestion: {first_num} {second_num}"
-                                      f"\nAnswer: ")
-
-        if correct_answer == int(player_answer):
-            print("Correct!")
-        else:
-            print(f"'{player_answer}' is wrong answer ;(. "
-                  f"Correct answer was {correct_answer}.\n"
-                  f"Let's try again, {player_name}!")
-            return
-
-    return print(f"Congratulations, {player_name}!")
+def run_gcd_engine_game():
+    run_game(func_numbers_and_gcd, GAME_INSTRUCTIONS['gcd'])
diff --git a/brain_games/games/prgss_engine.py b/brain_games/games/prgss_engine.py
index 19800e8..c458fc6 100644
--- a/brain_games/games/prgss_engine.py
+++ b/brain_games/games/prgss_engine.py
@@ -1,39 +1,21 @@
 import random
-import prompt
-from brain_games.game_const import (
-    PROGRESSION_LENGTH,
-    GAME_INSTRUCTIONS,
-    ROUND_COUNT,
-    GREETING
-)
+from brain_games.game_engine import run_game
+from brain_games.game_const import PROGRESSION_LENGTH, GAME_INSTRUCTIONS
 
 
-def func_progression():
-    player_name = prompt.string(f"{GREETING} ")
-    print(f"Hello, {player_name}!"
-          f"\n{GAME_INSTRUCTIONS['progression']}")
+def func_progression_and_missed_num():
+    start_num, step = random.randint(1, 5), random.randint(1, 5)
+    progression = []
 
-    for _ in range(ROUND_COUNT):
-        progression = []
+    for i in range(PROGRESSION_LENGTH):
+        progression.append(start_num + step * i)
 
-        start_num, step = random.randint(1, 5), random.randint(1, 5)
-        for i in range(PROGRESSION_LENGTH):
-            progression.append(start_num + step * i)
+    index_missed = random.randint(1, PROGRESSION_LENGTH - 1)
+    missed_num = progression[index_missed]
+    progression[index_missed] = '..'
+    progression_for_player = ' '.join(map(str, progression))
+    return progression_for_player, str(missed_num)
 
-        index_missed = random.randint(1, PROGRESSION_LENGTH - 1)
-        missed_num = progression[index_missed]
-        progression[index_missed] = '..'
-        progression_for_player = ' '.join(map(str, progression))
 
-        player_answer = prompt.string(f"\nQuestion: {progression_for_player}"
-                                      f"\nAnswer: ")
-
-        if missed_num == int(player_answer):
-            print("Correct!")
-        else:
-            print(f"'{player_answer}' is wrong answer ;(. "
-                  f"Correct answer was {missed_num}.\n"
-                  f"Let's try again, {player_name}!")
-            return
-
-    return print(f"Congratulations, {player_name}!")
+def run_func_progression_and_answer():
+    run_game(func_progression_and_missed_num, GAME_INSTRUCTIONS['progression'])
diff --git a/brain_games/games/prime_engine.py b/brain_games/games/prime_engine.py
index 3e80fc5..a165a0d 100644
--- a/brain_games/games/prime_engine.py
+++ b/brain_games/games/prime_engine.py
@@ -1,29 +1,20 @@
 import random
-import prompt
-from brain_games.game_const import ROUND_COUNT, GREETING, GAME_INSTRUCTIONS
+from brain_games.game_engine import run_game
+from brain_games.game_const import GAME_INSTRUCTIONS
 
 
-def func_prime():
-    player_name = prompt.string(f"{GREETING} ")
-    print(f"Hello, {player_name}!"
-          f"\n{GAME_INSTRUCTIONS['prime']}")
+def func_prime(num):
+    prime_number = 'no' if num <= 1 or any(
+        num % i == 0 for i in range(2, (num // 2 + 1))
+    ) else 'yes'
+    return prime_number
 
-    for _ in range(ROUND_COUNT):
-        prime_num = random.randint(1, 30)
 
-        correct_answer = 'no' if prime_num <= 1 or any(
-            prime_num % i == 0 for i in range(2, (prime_num // 2 + 1))
-        ) else 'yes'
+def get_prime_num_and_answer():
+    num = random.randint(1, 30)
+    prime = func_prime(num)
+    return num, prime
 
-        player_answer = prompt.string(f"\nQuestion: {prime_num}"
-                                      f"\nAnswer: ")
 
-        if correct_answer == player_answer:
-            print("Correct!")
-        else:
-            print(f"'{player_answer}' is wrong answer ;(. "
-                  f"Correct answer was '{correct_answer}'.\n"
-                  f"Let's try again, {player_name}!")
-            return
-
-    return print(f"Congratulations, {player_name}!")
+def run_prime_engine_game():
+    run_game(get_prime_num_and_answer, GAME_INSTRUCTIONS['prime'])
diff --git a/brain_games/scripts/brain_calc.py b/brain_games/scripts/brain_calc.py
index 1a71b6f..a70271e 100644
--- a/brain_games/scripts/brain_calc.py
+++ b/brain_games/scripts/brain_calc.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
-from brain_games.games.calc_engine import math_calc
+from brain_games.games.calc_engine import run_calc_engine_game
 
 
 def main():
-    math_calc()
+    run_calc_engine_game()
 
 
 if __name__ == '__main__':
diff --git a/brain_games/scripts/brain_even.py b/brain_games/scripts/brain_even.py
index bf22106..463387c 100644
--- a/brain_games/scripts/brain_even.py
+++ b/brain_games/scripts/brain_even.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
-from brain_games.games.even_engine import even_game
+from brain_games.games.even_engine import run_even_engine_game
 
 
 def main():
-    even_game()
+    run_even_engine_game()
 
 
 if __name__ == '__main__':
diff --git a/brain_games/scripts/brain_gcd.py b/brain_games/scripts/brain_gcd.py
index 312dfc5..03f9b24 100644
--- a/brain_games/scripts/brain_gcd.py
+++ b/brain_games/scripts/brain_gcd.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
-from brain_games.games.gcd_engine import func_gcd
+from brain_games.games.gcd_engine import run_gcd_engine_game
 
 
 def main():
-    func_gcd()
+    run_gcd_engine_game()
 
 
 if __name__ == '__main__':
diff --git a/brain_games/scripts/brain_prime.py b/brain_games/scripts/brain_prime.py
index d8daf5a..c49deb6 100644
--- a/brain_games/scripts/brain_prime.py
+++ b/brain_games/scripts/brain_prime.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
-from brain_games.games.prime_engine import func_prime
+from brain_games.games.prime_engine import run_prime_engine_game
 
 
 def main():
-    func_prime()
+    run_prime_engine_game()
 
 
 if __name__ == '__main__':
diff --git a/brain_games/scripts/brain_progression.py b/brain_games/scripts/brain_progression.py
index 2a653e1..e8836ff 100644
--- a/brain_games/scripts/brain_progression.py
+++ b/brain_games/scripts/brain_progression.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
-from brain_games.games.prgss_engine import func_progression
+from brain_games.games.prgss_engine import run_func_progression_and_answer
 
 
 def main():
-    func_progression()
+    run_func_progression_and_answer()
 
 
 if __name__ == '__main__':
diff --git a/poetry.lock b/poetry.lock
index da59537..49dd055 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -63,4 +63,4 @@ files = [
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.10"
-content-hash = "97129748ab2179cef92bf767692995f58bfb6184f6fbc073ff81f999be1ef6c9"
+content-hash = "795478d54f397bf15f055919ee025dc61380fc61fee145dfd9d88af8ade51a92"
diff --git a/pyproject.toml b/pyproject.toml
index 4a8e703..e8f1329 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,6 +11,7 @@ packages = [
 [tool.poetry.dependencies]
 python = "^3.10"
 prompt = "^0.4.1"
+flake8 = "^7.1.0"
 
 [tool.poetry.scripts]
 brain-games = "brain_games.scripts.brain_games:main"