#include <bits/stdc++.h>
const long long LL_INF = (long long)2e18 + 5;
using namespace std;
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  long long f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
const long long N = 1e6 + 10, mod = 1e9 + 7;
long long calc(long long a) { return (a * (a + 1)) / 2; }
void solve() {
  long long n, m;
  cin >> n >> m;
  long long total = calc(n);
  long long rem = n - m;
  long long mines = calc(rem / (m + 1)) * (m + 1 - (rem % (m + 1)));
  mines += (rem % (m + 1)) * calc(rem / (m + 1) + 1);
  cout << total - mines << '\n';
}
int32_t main() {
  clock_t clk = clock();
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long tt;
  cin >> tt;
  while (tt--) solve();
  cerr << "Time : " << (double(clock() - clk) * 1000.0 / CLOCKS_PER_SEC) + 15
       << " ms\n";
}
