/*
javac c.java && java c
*/

import java.io.*;
import java.util.*;

public class c {
	public static void main(String[] args) { new c(); }
	FS in = new FS();
	PrintWriter out = new PrintWriter(System.out);

	int t;
	long n, m;

	c() {
		t = in.nextInt();
		while (t-- > 0) {
		n = in.nextLong();
		m = in.nextLong();

		long ans = (n + 1) * n;
		ans >>= 1L;
		
		long opn = n - m;
		
		long q = opn / (m + 1);
		long r = opn % (m + 1);

		long min = (m + 1 - r) * (mult(q + 1, q) / 2);
		min += r * (mult(q + 2, q + 1) / 2);

		ans -= min;
		out.println(ans);
		}
		out.close();
	}

	long mult(long x, long y) { return x * y; }	
	
	int abs(int x) { return x < 0 ? -x : x; }
	long abs(long x) { return x < 0 ? -x : x; }
	double abs(double x) { return x < 0 ? -x : x; }
	int min(int x, int y) { return x < y ? x : y; }	
	int max(int x, int y) { return x > y ? x : y; }
	long min(long x, long y) { return x < y ? x : y; }	
	long max(long x, long y) { return x > y ? x : y; }
	double min(double x, double y) { return x < y ? x : y; }
	double max(double x, double y) { return x > y ? x : y; }
	int gcd(int x, int y) { while (y > 0) { x = y^(x^(y = x)); y %= x; } return x; }
	long gcd(long x, long y) { while (y > 0) { x = y^(x^(y = x)); y %= x; } return x; }
	long lcm(int x, int y) { return ((long) x / gcd(x, y)) * y; }
	long lcm(long x, long y) { return (x / gcd(x, y)) * y; }

	void sort(int[] arr) {
		int sz = arr.length, j;
		Random r = new Random();
		for (int i = 0; i < sz; i++) {
			j = r.nextInt(i + 1);
			arr[i] = arr[j]^(arr[i]^(arr[j] = arr[i]));
		} Arrays.sort(arr);
	}

	class FS {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens()) {
				try { st = new StringTokenizer(br.readLine()); }
				catch (Exception e) {}
			} return st.nextToken();
		}
		int nextInt() { return Integer.parseInt(next()); }
		long nextLong() { return Long.parseLong(next()); }
		double nextDouble() { return Double.parseDouble(next()); }
	}
}
