```
# Kamran's Calculator

def kamran_calculator():
    print("Welcome to Kamran's Calculator!")
    
    while True:
        print("\nOperations:")
        print("1. Addition")
        print("2. Subtraction")
        print("3. Multiplication")
        print("4. Division")
        print("5. Exit")
        
        choice = input("Choose an operation (1-5): ")
        
        if choice in ['1', '2', '3', '4']:
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
            
            if choice == '1':
                print(f"{num1} + {num2} = {num1 + num2}")
            elif choice == '2':
                print(f"{num1} - {num2} = {num1 - num2}")
            elif choice == '3':
                print(f"{num1} * {num2} = {num1 * num2}")
            elif choice == '4':
                if num2 != 0:
                    print(f"{num1} / {num2} = {num1 / num2}")
                else:
                    print("Error! Division by zero.")
        elif choice == '5':
            print("Goodbye!")
            break
        else:
            print("Invalid choice. Please choose again.")

kamran_calculator()
```