#include <bits/stdc++.h>
using namespace std;
long long MOD = 1000000007;
long long gcdf(long long a, long long b) {
  while (a != 0 && b != 0) {
    if (a > b) {
      a %= b;
    } else {
      b %= a;
    }
  }
  return max(a, b);
}
long long power(long long a, long long b, long long m) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % m;
    b /= 2;
    a = (a * a) % m;
  }
  return ans;
}
void boost() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
string st;
void dfs(vector<set<int>> &con, int fl, map<int, int> &flag) {
  if (flag[fl]) return;
  flag[fl] = 1;
  st.push_back('a' + fl);
  for (auto it = con[fl].begin(); it != con[fl].end(); it++) {
    dfs(con, *it, flag);
  }
  return;
}
int main() {
  boost();
  long long test = 1, i, j, k;
  cin >> test;
  while (test--) {
    long long n, m;
    cin >> n >> m;
    if (n == m) {
      cout << (n * (n + 1)) / 2 << endl;
      continue;
    }
    if (m == 0) {
      cout << 0 << endl;
      continue;
    }
    long long nn = n + 1, mm = m + 1;
    long long t1 = nn / mm - 1;
    long long tt1 = mm - nn % mm;
    long long t2 = nn / mm;
    long long tt2 = nn % mm;
    long long ans = ((t1 * (t1 + 1)) / 2) * tt1 + ((t2 * (t2 + 1)) / 2) * tt2;
    cout << (n * (n + 1)) / 2 - ans << endl;
  }
}
