Kind off help whit some clear messages.
>>> we_dot_do_homework_if_no_effort_is_shown = 2
>>> 1 % we_dot_do_homework_if_no_effort_is_shown
1
>>> 2 % we_dot_do_homework_if_no_effort_is_shown
0...

This code had been better without a class,and this is not the OOP way of thinking.
One function for Addition/Division....... can be shorten by eval()

>>> a = eval('5+8886/45*4554545')
>>> a...

There are several problem here.
Python 3.x only use input(raw_input only work for 2.x)

=assign variable(can not use in = in a if statement.
== Compares if the objects are equal

To get a...

input is a method that is build in to python.
And you can not do this input.find

>>> input.find

Traceback (most recent call last):
File "<pyshell#53>", line 1, in <module>
input.find...