#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
    ios::sync_with_stdio(0); cin.tie(0);
    ll N,k,a[9];
    int t;
    cin>>t;
    for(int c=1;c<=t;c++){
        cin>>N;
        k=1LL;
        for(int i=0;i<N;i++){
            cin>>a[i];
            k*=a[i];
        }
        ll den = 0;
        for(int i=0;i<N;i++) den+=k/a[i];
        ll num = N*k;
        ll d = __gcd(num,den);
        cout<<"Case "<<c<<": "<<num/d<<"/"<<den/d<<endl;
    }
}