#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long a, b, x, y, n;
    cin >> a >> b >> x >> y >> n;
    long long p = a - x, q = b - y;
    long long pp = min(p, n), qq = min(q, n);
    long long aa = a - pp, bb = b - qq;
    long long tt = a + b - n;
    if (p + q <= n)
      cout << x * y << endl;
    else {
      if (aa < bb)
        cout << aa * (tt - aa) << endl;
      else
        cout << bb * (tt - bb) << endl;
    }
  }
  return 0;
}
