#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << '\n';
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int inf = 0x3f3f3f3f;
long long infl = 0x3f3f3f3f3f3f3f3fLL;
long double infd = 1.0 / 0.0;
const long long MOD = 1e9 + 7;
const double pi = 2 * acos(0.0);
int main() {
  int tt = 1;
  cin >> tt;
  while (tt--) {
    long long n, m;
    cin >> n >> m;
    long long as = ((n) * (n + 1)) / 2;
    if (m == n) {
      cout << as << '\n';
      continue;
    }
    if (m == 0) {
      cout << 0 << '\n';
      continue;
    }
    long long x = min(n - m, m);
    long long z = max(1ll * 0, n - m - x);
    if (m >= n / 2) {
      as -= (n - m);
      cout << as << '\n';
      continue;
    }
    z = n - m;
    long long zr = z / (m + 1);
    if ((zr % (m + 1)) == 0) {
      zr = ((zr * (zr + 1)) / 2) * (m + 1);
      as -= zr;
    } else {
      long long zzz = zr;
      zr = ((zr * (zr + 1)) / 2) * (m - 1);
      long long de = n - m - (zzz * m);
      de += zzz;
      long long xs = de / 2;
      de = xs - de / 2;
      de = (de * (de + 1)) / 2;
      xs = (xs * (xs + 1)) / 2;
      de += xs;
      zr += de;
      as -= zr;
    }
    cout << as << '\n';
  }
  return 0;
}
