Calculator python3

[perfringo]

@perfringo actually it is not only the comparison of the while-loop causing the error, but the conversion to int.

Yes, you are correct and I made a mistake.

To catch more typing/error variations ('STOP', 'STop', etc) it is usually good to lower input.

input('Number: ').lower()

With Python 3.8 one can take advantage of walrus operator (no need to assign answer outside the loop):

while (answer := input('Number: ').lower()) != 'stop':
    # do stuff