You can use operators not only to perform operations by passing variables rather using class deirectly ,

Here's How :

#include "iostream"

class Arithmetic{
    public:
        int a; 

        Arithmetic(const int a) : a(a) {};

        int Add(const Arithmetic&b) const{
            return *this + b;
        };

        int Multiply(const Arithmetic&b) const {
            return operator*(b);
        };

        int operator+(const Arithmetic& b) const {
            return this->a + b.a;
        };

        int operator*(const Arithmetic& b) const {
            return this->a * b.a;
        };
};

int main(){
    Arithmetic a(10);
    Arithmetic b(12);

    std::cout << a.Add(b) << std::endl; 
    std::cout << a.Multiply(b) << std::endl;

    // OR 

    std::cout << a + b << std::endl;
    std::cout << a * b << std::endl;
    return EXIT_SUCCESS;
};

Here You can use the operators to directly operate between classes .