Simple Calculator with Python

simple-calculator.py

# addition function
def add(x, y):
    return x + y

# subtraction function
def subtract(x, y):
    return x - y

# multiplication function
def multiply(x, y):
    return x * y

# division function
def divide(x, y):
    return x / y


print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")
print("q.To quit")

while True:
    # take input from the user
    choice = input("Enter choice(1/2/3/4): ")

    # check if choice is one of the four options
    if choice in ('1', '2', '3', '4'):
        
        num1 = int(input("Enter first number: "))
        num2 = int(input("Enter second number: "))

        if choice == '1':
            print(num1, "+", num2, "=", add(num1, num2))

        elif choice == '2':
            print(num1, "-", num2, "=", subtract(num1, num2))

        elif choice == '3':
            print(num1, "*", num2, "=", multiply(num1, num2))

        elif choice == '4':
            print(num1, "/", num2, "=", divide(num1, num2))
       
        print("Let's do next calculation")

    elif choice == "q":
        print("Program ended.")
        break
    else:
        print("Invalid Input")