text: # Program make a simple calculator
  # 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")
  