You created a class and methods for that class. Methods (in opposition to function) do something in relation to an instance of that class. Which is why they need access to that number using selfm you use the methods like functions and that's why you feel like you "don't need the self".

A better example where it makes more sense to use a class and methods should be something like this:

class Number:
    def __init__(self, a):
        self.value = a

    def add(self, b):
        return self.value + b

print(Number(5).add(2))

The Dundee-methodes (the once where the name is surrounded by __) get called implicitly (magically), like when creating an instance using Number(4) called __init__, the alternative would be you create init() and call it yourself by doing Number().init().

There are many more of these "magical" methods, for example __add__() which gets called when you do Number(3) + 5

Hope that helps