Is it necessary to pass value of 'self' ?

[DeaD_EyE]

If you write a class, then do it right.
You're able to change the behavior of classes.
For example, you can add a method for add and subtract.

With your provided example:

class MyValue:
    def __init__(self, value):
        self.value = value
    def __add__(self, other):
        '''I am method in class Mathematics and not a function'''
        return self.value + other.value
 
    def __sub__(self, other):
        return self.value - other.value


my_val1 = MyValue(5)
my_val2 = MyValue(4)

print(my_val1 + my_val2)

Output:
9

And if you want to have functions, which takes left and right operand and doing something with it, then just use regular functions.

def add(a, b):
    return a + b


def sub(a, b):
    return a - b

# or use operator add and sub from operator module:

from operator import add, sub

print(add(1,2))
print(add(2,3))

Output:
from operator import add, sub

print(add(1,2))
print(add(2,3))

I guess you wanted the class, to stick the methods together.
If you have a regular method, then you have to instantiate the class to access the method.
A staticmethod does not supply the function with a reference to self nor to class.
To use this method, the class must be instantiated.

Finally, the classmethod allows calling methods directly on a class without creating an instance.

class Math:
    @classmethod
    def add(cls, a, b):
        return a + b

    @classmethod
    def sub(cls, a, b):
        return a - b


# calling the method on the class directly
print(Math.sub(1,2))

Output:
-1