Variadic Tuples Implementation

I've been trying to use Variadic Tuples on Generic Templates and Structs. The idea is to obtain the max and sum of a variadic tuple. So far I was able to obtain the required results but had to use Global static variables. I've posted the code below of the implementation.

    #include <iomanip>
    #include <complex>
    #include <cmath>
    #include <tuple>
    #include <string>
    #include <iostream>

    using namespace std;
    using namespace std::complex_literals;

    template<typename T>
    static T max;

    template<typename T>
    static T sum;

    template<typename T>
    static T average;

    template <typename T, typename Tuple, std::size_t N>
    struct Calculator
    {
    static void maximum(const Tuple& pack)
    {
    Calculator<T, Tuple, N - 1>::maximum(pack);
    T packValue = get<N - 1>(pack);
    if (packValue > max<T>)
    {
    //T max = get<0>(pack);
    //Try the above instead of the below code to calculate max
    max<T> = get<N - 1>(pack);
    }
    }

    static void summation(const Tuple& pack)
    {
    Calculator<T, Tuple, N - 1>::summation(pack);
    T packValue = get<N - 1>(pack);
    sum<T> += packValue;
    }

    static void averager(const Tuple& pack)
    {
    average<T> = sum<T> / N;
    }


    };

    template<typename T, typename Tuple>
    struct Calculator<T, Tuple, 1>
    {
    static void maximum(const Tuple& pack)
    {
    //T max = get<0>(pack);
    //Try the above instead of the below code to calculate max
    max<T> = get<0>(pack);
    }

    static void summation(const Tuple& pack)
    {
    sum<T> = get<0>(pack);
    }
    };




    int main()
    {
    tuple<double, double, double, double, double, double, double> t1 = make_tuple(16565.256, 45.539,     0.25, 1000.25, 1.25036, 35.66, 210.20);

    Calculator<double, tuple<double, double, double, double, double, double, double>, 7>::maximum(t1);

    cout << "Maximum is: " << max<double> << endl;

    Calculator<double, tuple<double, double, double, double, double, double, double>, 7>::summation(t1);
    cout << "Total Sum is: " << sum<double> << endl;

    Calculator<double, tuple<double, double, double, double, double, double, double>, 7>::averager(t1);
    cout << "Average is: " << average<double> << endl;



    std::complex<int> c2(22, 3);
    std::complex<int> ci(15, 41);
    tuple<std::complex<int>, std::complex<int> > ct1 = make_tuple(ci, c2);

    Calculator< std::complex<int>, tuple<std::complex<int>, std::complex<int> >, 2>::summation(ct1);

    cout << "Summation of complex numbers is: " << sum<std::complex<int>> << endl;

    }

My question, is it possible to implement a version that doesn't use Global static variables to hold the values of sum and max but an alternate implementation using Variadic Templates and Structs if possible?