import java.util.*;
import java.math.*;
import java.io.*;
import java.text.*;

public class practice {
    // heloo world nudniobv udivbo
    // buyfhsfnoisdfnoi
    public static void merge(int arr[], int l, int m, int r) {
        // Find sizes of two subarrays to be merged
        int n1 = m - l + 1;
        int n2 = r - m;

        /* Create temp arrays */
        int L[] = new int[n1];
        int R[] = new int[n2];

        /*Copy data to temp arrays*/
        for (int i = 0; i < n1; ++i)
            L[i] = arr[l + i];
        for (int j = 0; j < n2; ++j)
            R[j] = arr[m + 1 + j];


        /* Merge the temp arrays */

        // Initial indexes of first and second subarrays
        int i = 0, j = 0;

        // Initial index of merged subarry array
        int k = l;
        while (i < n1 && j < n2) {
            if (L[i] <= R[j]) {
                arr[k] = L[i];
                i++;
            } else {
                arr[k] = R[j];
                j++;
            }
            k++;
        }

        /* Copy remaining elements of L[] if any */
        while (i < n1) {
            arr[k] = L[i];
            i++;
            k++;
        }

        /* Copy remaining elements of R[] if any */
        while (j < n2) {
            arr[k] = R[j];
            j++;
            k++;
        }
    }

    // Main function that sorts arr[l..r] using
    // merge()
    public static void sort(int arr[], int l, int r) {
        if (l < r) {
            // Find the middle point
            int m = (l + r) / 2;

            // Sort first and second halves
            sort(arr, l, m);
            sort(arr, m + 1, r);

            // Merge the sorted halves
            merge(arr, l, m, r);
        }
    }

    public static int n;
    public static int m;
    public static int dis;
    public static ArrayList<Integer> a = new ArrayList<>();

    public static void hold_round() {
        for (int i = 0; i < n; i++) {
            int x = a.get(i);
            if (--(x) == 0)
                dis--;
        }
    }

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        long t = Long.parseLong(br.readLine());
        for (int xa = 0; xa < t; xa++) {
            StringTokenizer st = new StringTokenizer(br.readLine());
            long n = Long.parseLong(st.nextToken());
            long m = Long.parseLong(st.nextToken());
            long ans = (long)n * (long)(n + 1) / 2l;
            long z = n - m;
            long k = z / (m + 1);
            ans -= (long)(m +1) * (long)k * (long)(k + 1) / 2l;
            ans -= (long)(z % (m + 1)) * (long)(k + 1);
            System.out.println(ans);
        }
    }
}