#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const long long longinf = 1LL << 60;
const long long mod = 1e9 + 7;
const long double eps = 1e-10;
template <typename T1, typename T2>
inline void chmin(T1 &a, T2 b) {
  if (a > b) a = b;
}
template <typename T1, typename T2>
inline void chmax(T1 &a, T2 b) {
  if (a < b) a = b;
}
void solve() {
  long long n, m;
  cin >> n >> m;
  long long z = n - m;
  long long q = z / (m + 1);
  long long r = z % (m + 1);
  cout << (n + 1) * n / 2 -
              ((m + 1 - r) * (q + 1) * q / 2 + r * (q + 2) * (q + 1) / 2)
       << '\n';
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int T;
  cin >> T;
  while (T--) solve();
  return 0;
}
