# This function adds two numbers

def add(x, y):

    return x + y

 

# This function subtracts two numbers

def subtract(x, y):

    return x - y

 

# This function multiplies two numbers

def multiply(x, y):

    return x * y

 

# This function divides two numbers

def divide(x, y):

    return x / y

 

 

print("Select operation.")

print("1.Add")

print("2.Subtract")

print("3.Multiply")

print("4.Divide")

 

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 = float(input("Enter first number: "))

        num2 = float(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))

       

        # check if user wants another calculation

        # break the while loop if answer is no

        next_calculation = input("Let's do next calculation? (yes/no): ")

        if next_calculation == "no":

          break

   

    else:

        print("Invalid Input")

​

Output:

 

Select operation.

1.Add

2.Subtract

3.Multiply

4.Divide

Enter choice(1/2/3/4): 3

Enter first number: 15

Enter second number: 14

15.0 * 14.0 = 210.0

Let's do next calculation? (yes/no): no