diff --git a/calculator.py b/calculator.py
index cac6635..f100550 100644
--- a/calculator.py
+++ b/calculator.py
@@ -1,48 +1,56 @@
-# Custom function to read the two numbers.
-def read_numbers():
-    num1 = float(input('Enter first number: '))
-    num2 = float(input('Enter second number: '))
-    return num1, num2
-
-# Simple menu.
-print('Welcome to the calculator!')
-print('Please choose an operation:')
-print('    1. Addition')
-print('    2. Subtraction')
-print('    3. Multiplication')
-print('    4. Division')
-print('    5. Exit')
-
-# Main loop.
-while True:
-
-    choice = input('\nEnter your choice (1-5): ')
-
-    if choice in ('1', '2', '3', '4', '5'):
-        if choice == '1':
-            num1, num2 = read_numbers()
-            result = num1 + num2
-            print(f'Result: {result}')
-        
-        elif choice == '2':
-            num1, num2 = read_numbers()
-            result = num1 - num2
-            print(f'Result: {result}')
-        
-        elif choice == '3':
-            num1, num2 = read_numbers()
-            result = num1 * num2
-            print(f'Result: {result}')
-        
-        elif choice == '4':
-            try:
-                num1, num2 = read_numbers()
-                result = num1 / num2
-                print(f'Result: {result}')
-            except ZeroDivisionError:
-                print("Error: division by zero")
-        
-        elif choice == '5':
-            break
-    else:
-        print('Invalid Input')
\ No newline at end of file
+
+# Custom function to read the two numbers.
+def read_numbers():
+    num1 = float(input('Enter first number: '))
+    num2 = float(input('Enter second number: '))
+    return num1, num2
+
+# Simple menu.
+print('Welcome to the calculator!')
+print('Please choose an operation:')
+print('    1. Addition')
+print('    2. Subtraction')
+print('    3. Multiplication')
+print('    4. Division')
+print('    5. Exit')
+
+def main():
+    
+    # Main loop.
+    while True:
+        
+        choice = input('\nEnter your choice (1-5): ')
+
+        match choice:
+            case '1':
+                num1, num2 = read_numbers()
+                result = num1 + num2
+                print(f'Result: {result}')
+            
+            case '2':
+                num1, num2 = read_numbers()
+                result = num1 - num2
+                print(f'Result: {result}')
+            
+            case '3':
+                num1, num2 = read_numbers()
+                result = num1 * num2
+                print(f'Result: {result}')
+            
+            case '4':
+                try:
+                    num1, num2 = read_numbers()
+                    result = num1 / num2
+                    print(f'Result: {result}')
+                
+                except ZeroDivisionError:
+                    print("Error: division by zero")
+            
+            case '5':
+                break
+            
+            case _:
+                print('Invalid Input')
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file