Calculator: several options, changing the number

[j.crater]

Text on top of the window suggests the grader expects the function to return 0 upon completion. Try if this works:

    if select == 1:
        print("The result is:", number1 + number2)
        return 0
    elif select == 2:
        print("The result is:", (number1 - number2))
        return 0
    elif select == 3:
        print("The result is:", number1 * number2)
        return 0
    elif select == 4:
        print("The result is:", number1 / number2)
        return 0

Otherwise return is expected at a different point in program, which you should be able to figure from the task instructions.