#include <bits/stdc++.h>
#pragma GCC optimize "trapv"
using namespace std;
vector<string> split(const string& s, char c) {
  vector<string> v;
  stringstream ss(s);
  string x;
  while (getline(ss, x, c)) v.push_back(x);
  return move(v);
}
template <typename T, typename... Args>
inline string arrStr(T arr, int n) {
  stringstream s;
  s << "[";
  for (int i = 0; i < n - 1; i++) s << arr[i] << ",";
  s << arr[n - 1] << "]";
  return s.str();
}
inline void __evars_begin(int line) { cerr << "#" << line << ": "; }
template <typename T>
inline void __evars_out_var(vector<T> val) {
  cerr << arrStr(val, val.size());
}
template <typename T>
inline void __evars_out_var(T* val) {
  cerr << arrStr(val, 10);
}
template <typename T>
inline void __evars_out_var(T val) {
  cerr << val;
}
inline void __evars(vector<string>::iterator it) { cerr << endl; }
template <typename T, typename... Args>
inline void __evars(vector<string>::iterator it, T a, Args... args) {
  cerr << it->substr((*it)[0] == ' ', it->length()) << "=";
  __evars_out_var(a);
  cerr << "; ";
  __evars(++it, args...);
}
template <typename T_vector>
void output_vector(const T_vector& v, bool add_one = false, int start = -1,
                   int end = -1) {
  if (start < 0) start = 0;
  if (end < 0) end = int(v.size());
  for (int i = start; i < end; i++)
    cout << v[i] + (add_one ? 1 : 0) << (i < end - 1 ? ' ' : '\n');
}
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
template <class T, class H>
using umap = unordered_map<T, H, custom_hash>;
template <class T>
using uset = unordered_set<T, custom_hash>;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  clock_t clk = clock();
  int t = 1;
  cin >> t;
  auto calc = [&](long long n) { return n * (n + 1) / 2; };
  while (t--) {
    long long n, m;
    cin >> n >> m;
    cout << calc(n) - calc((n - m) / (m + 1)) * (m + 1) -
                ((n - m) / (m + 1) + 1) * ((n - m) % (m + 1))
         << endl;
  }
  cerr << '\n'
       << "Time (in s): " << double(clock() - clk) * 1.0 / CLOCKS_PER_SEC
       << '\n';
}
