#include <bits/stdc++.h>
using namespace std;
void optimise() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
}
long long int mod = 998244353;
long long int inf = 1e18 + 6;
void normalize(long long int &a) { a = (a + mod) % mod; }
long long int modmul(long long int a, long long int b) {
  a = a % mod;
  b = b % mod;
  normalize(a);
  normalize(b);
  return (a * b) % mod;
}
long long int modadd(long long int a, long long int b) {
  a = a % mod;
  b = b % mod;
  normalize(a);
  normalize(b);
  return (a + b) % mod;
}
long long int modsub(long long int a, long long int b) {
  a = a % mod;
  b = b % mod;
  normalize(a);
  normalize(b);
  return (a - b + mod) % mod;
}
long long int me(long long int x, long long int n) {
  x %= mod;
  if (n == 0) return 1;
  long long int u = me(x, n / 2) % mod;
  u = (u * u) % mod;
  if (n % 2) u = (u * x) % mod;
  return u;
}
long long int me1(long long int x, long long int n) {
  if (n == 0) return 1;
  long long int u = me1(x, n / 2);
  u = u * u;
  if (n % 2) u = u * x;
  return u;
}
inline long long int modInv(long long int a) { return me(a, mod - 2); }
inline long long int modDiv(long long int a, long long int b) {
  return modmul(a, modInv(b));
}
long long int __gcd(long long int a, long long int b) {
  if (b == 0)
    return a;
  else
    return __gcd(b, a % b);
}
void solve() {
  long long int n, m;
  cin >> n >> m;
  long long int n1 = n;
  n -= m;
  long long int k = n / (m + 1);
  if ((m + 1) > n) {
    cout << (n1 * (n1 + 1) / 2 - n);
    return;
  }
  n -= k * (m + 1);
  m = m + 1 - n;
  cout << (n1 * (n1 + 1) / 2) -
              (m * (k * (k + 1) / 2) + n * ((k + 1) * (k + 2)) / 2);
}
signed main() {
  optimise();
  long long int t;
  t = 1;
  cin >> t;
  cout << fixed << setprecision(3);
  while (t--) {
    solve();
    cout << "\n";
  }
}
