#include <bits/stdc++.h>                            //Aslan Mussinov

using namespace std;

typedef long long ll;
typedef vector <int> vi;
typedef pair <int,int> pii;

#define pb push_back
#define mp make_pair
#define F first
#define S second
#define endl '\n'
#define space ' '
#define sqr(x) ((x)*(x))
#define sz size()
#define TASK "a"

int test, n;

int main() { ios_base::sync_with_stdio(false); cin.tie(NULL);
    #ifndef ONLINE_JUDGE
    //freopen(TASK".in", "r", stdin);
    //freopen(TASK".out", "w", stdout);
    #endif

    cin >> test;
    while (test--)
    {
        cin >> n;
        ll sum = 0, sum2 = 0;
        for (ll i = 0, x; i < n; ++i)
        {
            cin >> x;
            x = abs(x);
            sum += x;
            sum2 += 1ll*sqr(x);
        }
        ll p = sum2*n - sqr(sum);
        ll q = n;
        ll g = __gcd(p, q);
        p /= g;
        q /= g;
        cout << p << '/' << q << endl;
    }

    #ifndef ONLINE_JUDGE
    cerr << endl << 1.0 * clock() / CLOCKS_PER_SEC << " s.";
    #endif
    return 0;
}