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

public class Main {
	static InputStream inputStream = System.in;
	static OutputStream outputStream = System.out;
	static InputReader in = new InputReader(inputStream);
	static PrintWriter out = new PrintWriter(outputStream);

	public static void main(String[] args) throws IOException {
		int t = 1;
		t = in.nextInt();
		while (t-- > 0) {
			solve();
		}
		out.close();

	}

	static int mod = 1000000007;

	public static class Pair {
		long val;
		int idx;

		public Pair(long v, int i) {
			this.val = v;
			this.idx = i;
		}

	}

	private static void solve() {
		long n = in.nextLong();
		long m = in.nextLong();

		long z = n - m;
		long pp = m + 1; // possible positions

		long len = z / pp;

		long cextra = z % pp; // extras
		long cxlen = len + 1;

		long ceach = z - cextra;
		long celen = len;
//		we have ex - with 1 extra zero
//		and each having equally divided zeroes of len 

//		all possible substrings - substrings with consecutive zeroes

		long tot = n * (n + 1) / 2;
		long zss = cextra * (cxlen * (cxlen + 1) / 2) + ceach * (len * (len + 1) / 2);
		long res = tot - zss;

		out.println(Math.max(0, res));
	}

//	int n = in.nextInt();
//	int[] a = new int[n];
//	for (int i = 0; i < n; i++) {
//		a[i] = in.nextInt();
//	}
	private static boolean pow2(int i) {
		return (i & (i - 1)) == 0;
	}

	private static void sort(int[] arr) {
		int n = arr.length;
		ArrayList<Integer> res = new ArrayList<>();
		for (int a : arr) {
			res.add(a);
		}
		Collections.sort(res);
		for (int i = 0; i < n; i++) {
			arr[i] = res.get(i);
		}
	}

	private static ArrayList<Integer> sieveOfEratosthenes(int n) {
		boolean[] arr = new boolean[n + 1];

		arr[0] = arr[1] = true;
		for (int i = 2; i * i <= n; i++) {
			if (!arr[i]) {
				for (int j = i * i; j <= n; j += i) {
					arr[j] = true;
				}
			}
		}
		ArrayList<Integer> primes = new ArrayList<>();
		for (int i = 2; i <= n; i++) {
			if (!arr[i]) {
				primes.add(i);
			}
		}
		return primes;
	}

	private static ArrayList<Integer> segmentedSieve(int s, int e) {
		int len = (int) (Math.sqrt(e) + 1);
		ArrayList<Integer> primes = sieveOfEratosthenes(len);
		boolean[] arr2 = new boolean[e - s + 1];
		if (s == 1) {
			arr2[0] = true;
		}
		ArrayList<Integer> res = new ArrayList<>();
		for (int p : primes) {

			int st = (int) (p * (Math.ceil((double) s / p)));
			if (st < s) {
				st += p;
			}
			if (st == p) {
				st += p;
			}
			for (int i = st; i <= e; i += p) {
				arr2[i - s] = true;
			}
		}
		for (int i = 0; i < arr2.length; i++) {
			if (!arr2[i]) {
				res.add(i + s);
			}
		}
		return res;
	}

	private static long pow(int n, int k) {
		long res = 1;
		long num = (long) n;
		while (k > 0) {
			if ((k & 1) == 1) {
				res = (res * num) % mod;
			}
			k /= 2;
			num = num * num % mod;
		}
		return res;
	}

	private static void set(int[] bits, int a) {
		for (int i = 31; i >= 0 && a > 0; i--) {
			int bit = a & 1;
			if (bit == 1) {
				bits[i]++;
			}
			a = a >> 1;
		}
	}

	private static void unset(int[] bits, int a) {
		for (int i = 31; i >= 0 && a > 0; i--) {
			int bit = a & 1;
			if (bit == 1) {
				bits[i]--;
			}
			a = a >> 1;
		}
	}

	private static int countDigits(int n) {
		int c = 0;
		while (n != 0) {
			c++;
			n /= 10;
		}
		return c;
	}

	private static int[] getRange(int a) {
		int min = 1;
		int t = a;
		while (--t > 0) {
			min = min * 10;
		}
		int max = 9;
		t = a;
		while (--t > 0) {
			max = max * 10 + 9;
		}
		return new int[] { min, max };
	}

	private static boolean palindrome(String str) {
		int s = 0;
		int e = str.length() - 1;
		while (s < e) {
			if (str.charAt(s) != str.charAt(e)) {
				return false;
			}
			s++;
			e--;
		}
		return true;
	}

	private static void reverse(int[] arr, int s, int e) {
		while (s < e) {
			int temp = arr[s];
			arr[s++] = arr[e];
			arr[e--] = temp;
		}
	}

	private static int getMax(int[] arr, int s, int e) {
		int maxi = s;
		for (int i = s + 1; i <= e; i++) {
			if (arr[i] > arr[maxi]) {
				maxi = i;
			}
		}
		return maxi;
	}

	private static int getMin(int[] arr, int s, int e) {
		int mini = s;
		for (int i = s + 1; i <= e; i++) {
			if (arr[i] < arr[mini]) {
				mini = i;
			}
		}
		return mini;
	}

	private static long lcm(long n1, long n2) {
		return (n1 * n2) / gcd(n1, n2);
	}

	private static long gcd(long num1, long num2) {
		if (num2 == 0) {
			return num1;
		}
		return gcd(num2, num1 % num2);
	}

	private static int lcm(int n1, int n2) {
		return (n1 * n2) / gcd(n1, n2);
	}

	private static int gcd(int num1, int num2) {
		if (num2 == 0) {
			return num1;
		}
		return gcd(num2, num1 % num2);
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public String nextLine() throws IOException {
			return reader.readLine().trim();
		}
	}
}